Document:

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                                                                     Exhibit 4.9
                                                                     -----------

                           AMERICAN TOWER CORPORATION

                                     ISSUER

                         9 3/8% SENIOR NOTES DUE 2009

                          DATED AS OF JANUARY 31, 2001

                              THE BANK OF NEW YORK

                                     TRUSTEE
<PAGE>

                            CROSS-REFERENCE TABLE*
<TABLE>
<CAPTION>

Trust Indenture Act Section                                                Indenture Section
---------------------------                                                -----------------
<S>                                                                        <C>
310(a)(1).............................................................          7.10
   (a)(2).............................................................          7.10
   (a)(3).............................................................          N.A.
   (a)(4).............................................................          N.A.
   (a)(5).............................................................          7.10
   (b)................................................................          7.10
   (c)................................................................          N.A.
311(a)................................................................          7.11
   (b)................................................................          7.11
   (c)................................................................          N.A.
312(a)................................................................          2.05
   (b)................................................................         11.03
   (c)................................................................         11.03
313(a)................................................................          7.06
   (b)(1).............................................................          7.06
   (b)(2).............................................................       7.06; 7.07
   (c)................................................................      7.06; 11.02
   (d)................................................................          7.06
314(a)................................................................   4.03; 4.04; 11.02
   (b)................................................................          N.A.
   (c)(1).............................................................         11.04
   (c)(2).............................................................         11.04
   (c)(3).............................................................          N.A.
   (d)................................................................          N.A.
   (e)................................................................         11.05
   (f)................................................................          N.A.
315(a)................................................................          7.01
   (b)................................................................      7.05; 11.02
   (c)................................................................          7.01
   (d)................................................................          7.01
   (e)................................................................          6.11
316(a)(last sentence).................................................          2.09
   (a)(1)(A)..........................................................          6.05
   (a)(1)(B)..........................................................          6.04
   (a)(2).............................................................          N.A.
   (b)................................................................          6.07
   (c)................................................................          2.12
317(a)(1).............................................................          6.08
   (a)(2).............................................................          6.09
   (b)................................................................          2.04
318(a)................................................................         11.01
   (b)................................................................          N.A.
   (c)................................................................         11.01
N.A. means not applicable
</TABLE>
------------------
     *     This Cross Reference Table is not part of the Indenture.

                                       i
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                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                            Page
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<S>              <C>                                                                                        <C>
                                                   ARTICLE 1

                                  DEFINITIONS AND INCORPORATION BY REFERENCE

Section 1.01.    Definitions.................................................................................  1
Section 1.02.    Other Definitions........................................................................... 29
Section 1.03.    Incorporation by Reference of Trust Indenture Act........................................... 29
Section 1.04.    Rules of Construction....................................................................... 30

                                                   ARTICLE 2

                                                   THE NOTES

Section 2.01.    Form and Dating............................................................................. 30
Section 2.02.    Execution and Authentication................................................................ 32
Section 2.03.    Registrar and Paying Agent.................................................................. 33
Section 2.04.    Paying Agent to Hold Money in Trust......................................................... 33
Section 2.05.    Holder Lists................................................................................ 33
Section 2.06.    Transfer and Exchange....................................................................... 34
Section 2.07.    Replacement Notes........................................................................... 40
Section 2.08.    Outstanding Notes........................................................................... 40
Section 2.09.    Treasury Notes.............................................................................. 41
Section 2.10.    Temporary Notes............................................................................. 41
Section 2.11.    Cancellation................................................................................ 41
Section 2.12.    Defaulted Interest.......................................................................... 41
Section 2.13.    CUSIP Numbers............................................................................... 42

                                                   ARTICLE 3

                                           REDEMPTION AND PREPAYMENT

Section 3.01.    Notices to Trustee.......................................................................... 42
Section 3.02.    Selection of Notes to Be Redeemed........................................................... 42
Section 3.03.    Notice of Redemption........................................................................ 42
Section 3.04.    Effect of Notice of Redemption.............................................................. 43
Section 3.05.    Deposit of Redemption Price................................................................. 44
Section 3.06.    Notes Redeemed in Part...................................................................... 44
Section 3.07.    Optional Redemption......................................................................... 44
Section 3.08.    Mandatory Redemption........................................................................ 45
Section 3.09.    Offer to Purchase by Application of Excess Proceeds......................................... 45
</TABLE>

                                      ii
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<TABLE>
<CAPTION>
                                                   ARTICLE 4

                                                   COVENANTS
<S>              <C>                                                                                        <C>
Section 4.01.    Payment of Notes.............................................................................47
Section 4.02.    Maintenance of Office or Agency..............................................................48
Section 4.03.    Reports......................................................................................48
Section 4.04.    Compliance Certificate.......................................................................49
Section 4.05.    Taxes........................................................................................50
Section 4.06.    Stay, Extension and Usury Laws...............................................................50
Section 4.07.    Restricted Payments..........................................................................50
Section 4.08.    Dividend and Other Payment Restrictions Affecting Subsidiaries...............................54
Section 4.09.    Incurrence of Indebtedness and Issuance of Preferred Stock...................................57
Section 4.10.    Asset Sales..................................................................................61
Section 4.11.    Transactions with Affiliates.................................................................62
Section 4.12.    Liens........................................................................................64
Section 4.13.    Corporate Existence..........................................................................64
Section 4.14.    Offer to Repurchase Upon Change of Control...................................................64
Section 4.15.    Sale and Leaseback Transactions..............................................................66
Section 4.16.    Limitation on Issuances and Sales of Capital Stock of Restricted Subsidiaries................67
Section 4.17.    Limitation on Issuances of Guarantees of Indebtedness........................................68
Section 4.18.    Covenant Suspension..........................................................................68

                                                   ARTICLE 5

                                                   SUCCESSORS

Section 5.01.    Merger, Consolidation, or Sale of Assets.....................................................69
Section 5.02.    Successor Corporation Substituted............................................................71

                                                   ARTICLE 6

                                             DEFAULTS AND REMEDIES

Section 6.01.    Events of Default............................................................................71
Section 6.02.    Acceleration.................................................................................73
Section 6.03.    Other Remedies...............................................................................73
Section 6.04.    Waiver of Past Defaults......................................................................73
Section 6.05.    Control by Majority..........................................................................74
Section 6.06.    Limitation on Suits..........................................................................74
Section 6.07.    Rights of Holders of Notes to Receive Payment................................................74
Section 6.08.    Collection Suit by Trustee...................................................................75
Section 6.09.    Trustee May File Proofs of Claim.............................................................75
Section 6.10.    Priorities...................................................................................75
</TABLE>

                                      iii
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<TABLE>
<CAPTION>
<S>             <C>                                                                                          <C>
Section 6.11.    Undertaking for Costs........................................................................76

                                                   ARTICLE 7

                                                    TRUSTEE

Section 7.01.    Duties of Trustee............................................................................76
Section 7.02.    Rights of Trustee............................................................................77
Section 7.03.    Individual Rights of Trustee.................................................................78
Section 7.04.    Trustee's Disclaimer.........................................................................78
Section 7.05.    Notice of Defaults...........................................................................78
Section 7.06.    Reports by Trustee to Holders of the Notes...................................................78
Section 7.07.    Compensation and Indemnity...................................................................79
Section 7.08.    Replacement of Trustee.......................................................................80
Section 7.09.    Successor Trustee by Merger, etc.............................................................81
Section 7.10.    Eligibility; Disqualification................................................................81
Section 7.11.    Preferential Collection of Claims Against Company............................................81
Section 7.12.    Trustee's Application for Instructions from the Company......................................81

                                                   ARTICLE 8

                                    LEGAL DEFEASANCE AND COVENANT DEFEASANCE

Section 8.01.    Option to Effect Legal Defeasance or Covenant Defeasance.....................................81
Section 8.02.    Legal Defeasance and Discharge...............................................................82
Section 8.03.    Covenant Defeasance..........................................................................82
Section 8.04.    Conditions to Legal or Covenant Defeasance...................................................83
Section 8.05.    Deposited Money and Government Securities to be Held in Trust; Other
                   Miscellaneous Provisions...................................................................84
Section 8.06.    Repayment to Company.........................................................................85
Section 8.07.    Reinstatement................................................................................85

                                                   ARTICLE 9

                                       AMENDMENT, SUPPLEMENT AND WAIVER

Section 9.01.    Without Consent of Holders of Notes..........................................................86
Section 9.02.    With Consent of Holders of Notes.............................................................86
Section 9.03.    Compliance with Trust Indenture Act..........................................................88
Section 9.04.    Revocation and Effect of Consents............................................................88
Section 9.05.    Notation on or Exchange of Notes.............................................................88
Section 9.06.    Trustee to Sign Amendments, etc..............................................................89
</TABLE>

                                      iv
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<TABLE>
<CAPTION>

                                                   ARTICLE 10

                                                 NOTE GUARANTEES
<S>              <C>                                                                                         <C>
Section 10.01.   Guarantee....................................................................................89
Section 10.02.   Limitation on Guarantor Liability............................................................90
Section 10.03.   Execution and Delivery of Note Guarantee.....................................................90
Section 10.04.   Guarantors May Consolidate, etc., on Certain Terms...........................................91
Section 10.05.   Releases Following Sale of Assets............................................................92

                                                   ARTICLE 11

                                                 MISCELLANEOUS

Section 11.01.   Trust Indenture Act Controls.................................................................92
Section 11.02.   Notices......................................................................................92
Section 11.03.   Communication by Holders of Notes with Other Holders of Notes................................93
Section 11.04.   Certificate and Opinion as to Conditions Precedent...........................................94
Section 11.05.   Statements Required in Certificate or Opinion................................................94
Section 11.06.   Rules by Trustee and Agents..................................................................94
Section 11.07.   No Personal Liability of Directors, Officers, Employees and Stockholders.....................94
Section 11.08.   Governing Law................................................................................95
Section 11.09.   No Adverse Interpretation of Other Agreements................................................95
Section 11.10.   Successors...................................................................................95
Section 11.11.   Severability.................................................................................95
Section 11.12.   Counterpart Originals........................................................................95
Section 11.13.   Table of Contents, Headings, etc.............................................................95
</TABLE>

                                    EXHIBITS

Exhibit A         FORM OF NOTE

Exhibit B         FORM OF SUPPLEMENTAL INDENTURE TO BE DELIVERED BY SUBSEQUENT
                  GUARANTORS

Exhibit C         FORM OF NOTATION OF GUARANTEE

Exhibit D         FORM OF REGULATION S CERTIFICATE

Exhibit E         FORM OF RESTRICTED NOTES CERTIFICATE

Exhibit F         FORM OF UNRESTRICTED NOTES CERTIFICATE

                                       v
<PAGE>

     INDENTURE dated as of January 31, 2001 between American Tower Corporation,
a Delaware corporation (the "Company"), and The Bank of New York, a New York
banking corporation, as trustee (the "Trustee").

     The Company and the Trustee agree as follows for the benefit of each other
and for the equal and ratable benefit of the Holders of the 9 3/8% Senior Notes
Due 2009 (each, a "Note", and, collectively, the "Notes"):

                                    ARTICLE 1

                          DEFINITIONS AND INCORPORATION
                                  BY REFERENCE

Section 1.01. Definitions.

     "Acquired Debt" means, with respect to any specified Person:

          (1)  Indebtedness of any other Person existing at the time such other
               Person is merged with or into or became a Subsidiary of such
               specified Person, including, without limitation, Indebtedness
               incurred in connection with, or in contemplation of, such other
               Person merging with or into or becoming a Subsidiary of such
               specified Person; and

          (2)  Indebtedness secured by a Lien encumbering any asset acquired by
               such specified Person.

     "Additional Interest" has the meaning set forth in the form of Note
attached as Exhibit A. Unless the context otherwise requires, references herein
to "interest" on the Notes shall include Additional Interest.

     "Adjusted Consolidated Cash Flow" means, as of any date of determination,
the sum of:

          (1)  the Consolidated Cash Flow of the Company for the four most
               recent full fiscal quarters ending immediately prior to such date
               for which internal financial statements are available, less the
               Company's Tower Cash Flow for such four-quarter period; plus

          (2)  the product of four times the Company's Tower Cash Flow for the
               most recent fiscal quarter for which internal financial
               statements are available.

     For purposes of making the computation referred to above:

          (1)  acquisitions that have been made by the Company or any of its
               Restricted Subsidiaries, including through mergers or
               consolidations and including any related financing transactions,
               during the reference period or subsequent to such reference
               period and on or prior to the calculation date
<PAGE>

               shall be deemed to have occurred on the first day of the
               reference period and Consolidated Cash Flow for such reference
               period shall be calculated without giving effect to clause (2) of
               the proviso set forth in the definition of Consolidated Net
               Income;

          (2)  the Consolidated Cash Flow attributable to discontinued
               operations, as determined in accordance with GAAP, and operations
               or businesses disposed of prior to the calculation date, shall be
               excluded; and

          (3)  the corporate development expense of the Company and its
               Restricted Subsidiaries calculated in a manner consistent with
               the audited financial statements of the Company included in the
               Offering Circular shall be added to Consolidated Cash Flow to the
               extent it was included in computing Consolidated Net Income.

     "Affiliate" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person. For purposes of this definition, "control"
(including, with correlative meanings, the terms "controlling," "controlled by"
and "under common control with"), as used with respect to any Person, shall mean
the possession, directly or indirectly, of the power to direct or cause the
direction of the management or policies of such Person, whether through the
ownership of voting securities, by agreement or otherwise; provided that
beneficial ownership of 10% or more of the Voting Stock of a Person shall be
deemed to be control. No natural person who is an executive officer or director
of a Person shall, solely by virtue of such position, be deemed to control such
Person.

     "Agent" means any Registrar, Paying Agent or co-registrar.

     "Applicable Premium" means, with respect to any Note on any redemption
date, the greater of:

          (1)  1.0% of the principal amount of the Note, and

          (2)  the excess of (a) the present value at such redemption date of
               (i) the redemption price of the Note at February 1, 2005 (such
               redemption price being set forth in the table appearing in
               Section 3.07(a) of this Indenture) plus (ii) all required
               interest payments due on the Note during the period from such
               redemption date through February 1, 2005 (excluding accrued but
               unpaid interest), computed using a discount rate equal to the
               Treasury Rate as of such redemption date plus 50 basis points,
               over (b) the principal amount of the Note, if greater.

     "Applicable Procedures" means, with respect to any transfer or exchange of
or for beneficial interests in any Global Note, the rules and procedures of the
Depositary, Euroclear and Clearstream that apply to such transfer or exchange.

                                       2
<PAGE>

     "Asset Sale" means:

          (1)  the sale, lease, conveyance or other disposition of any assets or
               rights (including, without limitation, by way of a sale and
               leaseback or merger); provided that the sale, lease, conveyance
               or other disposition of all or substantially all of the assets of
               the Company and its Subsidiaries taken as a whole will be
               governed by Section 4.14 and Article 5 hereof and not by Section
               4.10 hereof; and

          (2)  the issue or sale by the Company or any of its Restricted
               Subsidiaries of Equity Interests of any of the Company's
               Restricted Subsidiaries (other than directors' qualifying shares
               or shares required by applicable law to be held by a Person other
               than the Company or a Restricted Subsidiary),

     in the case of either clause (1) or (2), whether in a single transaction or
     a series of related transactions:

               (a)  that have a fair market value in excess of $1.0 million; or

               (b)  for net proceeds in excess of $1.0 million.

     Notwithstanding the foregoing, the following items shall not be deemed to
be Asset Sales:

          (1)  a transfer of assets by the Company to a Restricted Subsidiary or
               by a Restricted Subsidiary to the Company or to another
               Restricted Subsidiary;

          (2)  an issuance of Equity Interests by a Subsidiary to the Company or
               to another Restricted Subsidiary;

          (3)  a Restricted Payment that is permitted by Section 4.07 hereof;

          (4)  a transfer of Equity Interests of an Unrestricted Subsidiary or
               an issue of Equity Interests by an Unrestricted Subsidiary;

          (5)  grants of leases or licenses, or the sale or other disposition of
               inventory, in the ordinary course of business;

          (6)  dispositions of Cash Equivalents; and

          (7)  the issuance of Equity Interests of the Company.

                                       3
<PAGE>

     "Attributable Debt" in respect of a sale and leaseback transaction means,
at the time of determination, the present value (discounted at the rate of
interest implicit in such transaction, determined in accordance with GAAP) of
the obligation of the lessee for net rental payments during the remaining term
of the lease included in such sale and leaseback transaction (including any
period for which such lease has been extended or may, at the option of the
lessor, be extended).

     "Bankruptcy Law" means Title 11, U.S. Code or any similar federal or state
law for the relief of debtors.

     "Board of Directors" means the Board of Directors of the Company, or any
authorized committee of the Board of Directors.

     "Business Day" means any day other than a Legal Holiday.

     "Capital Lease Obligation" means, at the time any determination thereof is
to be made, the amount of the liability in respect of a capital lease that would
at such time be required to be capitalized on a balance sheet in accordance with
GAAP.

     "Capital Stock" means:

          (1)  in the case of a corporation, corporate stock;

          (2)  in the case of an association or business entity, any and all
               shares, interests, participations, rights or other equivalents
               (however designated) of corporate stock;

          (3)  in the case of a partnership or limited liability company,
               partnership or membership interests (whether general or limited);
               and

          (4)  any other interest or participation that confers on a Person the
               right to receive a share of the profits and losses of, or
               distributions of assets of, the issuing Person.

     "Cash Equivalents" means:

          (1)  marketable, direct obligations of the United States of America,
               its agencies and instrumentalities maturing within 365 days of
               the date of purchase;

          (2)  commercial paper and other short-term obligations of business
               savings accounts issued by corporations, each of which shall have
               a combined net worth of at least $100,000,000 and each of which
               conducts a substantial part of its business in the United States
               of America, maturing within 270 days from the date of original
               issue thereof, and whose issuer is, at the time of purchase,
               rated "P-2" or better by Moody's or "A-2" or better by S&P;

                                       4
<PAGE>

          (3)  repurchase agreements, bankers' acceptances and domestic and
               Eurodollar certificates of deposit maturing within 365 days of
               the date of purchase which are issued by, or time deposits
               maintained with

               (a)  a United States national or state bank (or any domestic
                    branch of a foreign bank) subject to supervision and
                    examination by federal or state banking or depository
                    institution authorities and having capital, surplus and
                    undivided profits totaling more than $100,000,000 and rated
                    "A" or better by Moody's or S&P,

               (b)  a broker/dealer (acting as principal) registered as a broker
                    or a dealer under Section 15 of the Exchange Act the
                    unsecured short-term debt obligations of which are rated
                    "P-1" by Moody's and at least "A-1" by S&P at the date of
                    purchase, or

               (c)  an unrated broker/dealer, acting as principal, that is a
                    Wholly Owned Restricted Subsidiary (but substituting
                    "Subsidiary" for "Restricted Subsidiary" in the definition
                    thereof) of a non-bank or bank holding company, the
                    unsecured short-term debt obligations of which are rated
                    "P-1" by Moody's and at least "A-1" by S&P at the date of
                    purchase; and

          (4)  money market funds having a rating from Moody's and S&P in the
               highest investment category granted thereby.

     "Change of Control" means the occurrence of any of the following:

          (1)  the sale, lease, transfer, conveyance or other disposition (other
               than by way of merger or consolidation), in one or a series of
               related transactions, of all or substantially all of the assets
               of the Company and its Restricted Subsidiaries, taken as a whole
               to any "person" (as such term is used in Section 13(d)(3) of the
               Exchange Act) other than the Principal or a Related Party of the
               Principal;

          (2)  the adoption of a plan relating to the liquidation or dissolution
               of the Company;

          (3)  the consummation of any transaction (including, without
               limitation, any merger or consolidation) the result of which is
               that any "person" (as defined above), other than the Principal
               and his Related Parties, becomes the "beneficial owner" (as such
               term is defined in Rule 13d-3 and Rule 13d-5 under the Exchange
               Act, except that a person shall be deemed to have "beneficial
               ownership" of all securities that such person has the right to
               acquire, whether such right is currently exercisable or is
               exercisable only upon the occurrence of a subsequent condition),
               directly or indirectly, of more than 50% of the Voting Stock of
               the Company (measured by

                                       5
<PAGE>

               voting power rather than number of shares); provided that
               transfers of Equity Interests in the Company between or among the
               beneficial owners of the Company's Equity Interests, as of the
               Issue Date, will not be deemed to cause a Change of Control under
               this clause (3) so long as no single Person together with its
               Affiliates acquires a beneficial interest in more of the Voting
               Stock of the Company than is at the time collectively
               beneficially owned by the Principal and his Related Parties;

          (4)  the first day on which a majority of the members of the Board of
               Directors are not Continuing Directors; or

          (5)  the Company consolidates with, or merges with or into, any
               Person, or any Person consolidates with, or merges with or into,
               the Company, in any such event pursuant to a transaction in which
               any of the outstanding Voting Stock of the Company is converted
               into or exchanged for cash, securities or other property, other
               than any such transaction where:

               (a)  the Voting Stock of the Company outstanding immediately
                    prior to such transaction is converted into or exchanged for
                    Voting Stock (other than Disqualified Stock) of the
                    surviving or transferee Person constituting a majority of
                    the outstanding shares of such Voting Stock of such
                    surviving or transferee Person (immediately after giving
                    effect to such issuance); or

               (b)  the Principal and his Related Parties own a majority of such
                    outstanding shares after such transaction.

     "Clearstream" means Clearstream Banking S.A. (or any successor securities
clearing agency).

     "Company" means American Tower Corporation, and any and all successors
thereto.

     "Completed Broadcast Tower" means any communications transmission tower of
at least 500 feet owned or managed by the Company or any of its Restricted
Subsidiaries that, as of any date of determination:

          (1)  has at least one broadcast tenant that has executed a definitive
               lease with the Company or any of its Restricted Subsidiaries,
               which lease is producing revenue with respect to the tower as of
               the date of determination; and

          (2)  has capacity for at least one tenant in addition to the tenant
               referred to in clause (1) of this definition.

                                       6
<PAGE>

     "Completed Tower" means any communications transmission tower, other than a
Completed Broadcast Tower, owned or managed by the Company or any of its
Restricted Subsidiaries that, as of any date of determination:

          (1)  has at least one wireless communications or broadcast tenant that
               has executed a definitive lease with the Company or any of its
               Restricted Subsidiaries, which lease is producing revenue with
               respect to the tower as of the date of determination; and

          (2)  has capacity for at least two tenants in addition to the tenant
               referred to in clause (1) of this definition.

     "Consolidated Cash Flow" means, with respect to any Person for any period,
the Consolidated Net Income of such Person for such period; plus

          (1)  provision for taxes based on income or profits of such Person and
               its Restricted Subsidiaries for such period, to the extent that
               such provision for taxes was included in computing such
               Consolidated Net Income; plus

          (2)  consolidated interest expense of such Person and its Restricted
               Subsidiaries for such period, whether paid or accrued and whether
               or not capitalized (including, without limitation, amortization
               of debt issuance costs and original issue discount, non-cash
               interest payments, the interest component of any deferred payment
               obligations, the interest component of all payments associated
               with Capital Lease Obligations, commissions, discounts and other
               fees and charges incurred in respect of letters of credit or
               bankers' acceptance financings, and net payments (if any)
               pursuant to Hedging Obligations), to the extent that any such
               expense was deducted in computing such Consolidated Net Income;
               plus

          (3)  depreciation, amortization (including amortization of goodwill
               and other intangibles) and other non-cash expenses (including
               write-offs or write-downs of goodwill and other intangible assets
               but excluding any such non- cash expense to the extent that it
               represents an accrual of or reserve for cash expenses in any
               future period) of such Person and its Restricted Subsidiaries for
               such period to the extent that such depreciation, amortization
               and other non-cash expenses were deducted in computing such
               Consolidated Net Income; minus

          (4)  non-cash items increasing such Consolidated Net Income for such
               period (excluding any items that were accrued in the ordinary
               course of business),

in each case on a consolidated basis and determined in accordance with GAAP.

     "Consolidated Indebtedness" means, with respect to any Person as of any
date of determination, the sum, without duplication, of

                                       7
<PAGE>

          (1)  the total amount of Indebtedness of such Person and its
               Restricted Subsidiaries; plus

          (2)  the total amount of Indebtedness of any other Person, to the
               extent that such Indebtedness has been Guaranteed by the referent
               Person or one or more of its Restricted Subsidiaries; plus

          (3)  the aggregate liquidation value of all Disqualified Stock of such
               Person and all preferred stock of Restricted Subsidiaries of such
               Person,

in each case, determined on a consolidated basis in accordance with GAAP.

     "Consolidated Interest Expense" means, with respect to any Person for any
period:

          (1)  the consolidated interest expense of such Person and its
               Restricted Subsidiaries for such period determined in accordance
               with GAAP, whether paid or accrued and whether or not capitalized
               (including, without limitation, amortization of debt issuance
               costs and original issue discount, non-cash interest payments,
               the interest component of any deferred payment obligations, the
               interest component of all payments associated with Capital Lease
               Obligations, commissions, discounts and other fees and charges
               incurred in respect of letter of credit or bankers' acceptance
               financings, and net payments, if any, pursuant to Hedging
               Obligations); plus

          (2)  all preferred stock dividends paid or accrued in respect of the
               Company's and its Restricted Subsidiaries' preferred stock to
               Persons other than the Company or a Wholly Owned Restricted
               Subsidiary of the Company other than preferred stock dividends
               paid by the Company in shares of preferred stock that is not
               Disqualified Stock.

     "Consolidated Net Income" means, with respect to any Person for any period,
the aggregate of the Net Income of such Person and its Restricted Subsidiaries
for such period, on a consolidated basis, determined in accordance with GAAP;
provided that

          (1)  the Net Income of any Person other than the Company that is not a
               Restricted Subsidiary or that is accounted for by the equity
               method of accounting shall be included only to the extent of the
               amount of dividends or distributions paid in cash to the referent
               Person or a Restricted Subsidiary thereof and shall not be
               included if a net loss;

          (2)  the Net Income (and net loss) of any Person acquired in a pooling
               of interests transaction for any period prior to the date of such
               acquisition shall be excluded;

                                       8
<PAGE>

          (3)  the cumulative effect of a change in accounting principles shall
               be excluded; and

          (4)  the Net Income (and net loss) of any Unrestricted Subsidiary
               shall be excluded whether or not distributed to the Company or
               one of its Restricted Subsidiaries.

     "Consolidated Tangible Assets" means, with respect to the Company, the
total consolidated assets of the Company and its Restricted Subsidiaries, less
the total intangible assets of the Company and its Restricted Subsidiaries, as
shown on the most recent internal consolidated balance sheet of the Company and
such Restricted Subsidiaries calculated on a consolidated basis in accordance
with GAAP.

     "Continuing Directors" means, as of any date of determination, any member
of the Board of Directors who:

          (1)  was a member of such Board of Directors on the Issue Date;

          (2)  was nominated for election or elected to such Board of Directors
               with the approval of a majority of the Continuing Directors who
               were members of such Board of Directors at the time of such
               nomination or election; or

          (3)  is a designee of the Principal or was nominated by the Principal.

     "Convertible Notes" means up to $300.0 million aggregate principal amount
of 6.25% Convertible Notes Due 2009 of the Company issued pursuant to the
Indenture, dated as of October 4, 1999, between the Company and The Bank of New
York, as trustee, up to $425.5 million aggregate principal amount of 2.25%
Convertible Notes Due 2009 of the Company issued pursuant to the Indenture,
dated as of October 4, 1999, between the Company and The Bank of New York, as
trustee, and up to $450.0 million aggregate principal amount of 5.0% Convertible
Notes Due 2010 of the Company issued pursuant to the Indenture, dated as of
February 15, 2000, between the Company and The Bank of New York, as trustee.

     "Corporate Trust Office of the Trustee" shall be at the address of the
Trustee specified in Section 11.02 hereof or such other address as to which the
Trustee may give notice to the Company.

     "Credit Facilities" means one or more debt facilities (including, without
limitation, the Senior Credit Facility) or commercial paper facilities with
banks or other institutional lenders providing for revolving credit loans, term
loans, receivables financing (including through the sale of receivables to such
lenders or to special purpose entities formed to borrow from such lenders
against such receivables) or letters of credit, in each case, as amended,
restated, modified, renewed, refunded, replaced or refinanced in whole or in
part from time to time.

     "Custodian" means the Trustee, as custodian with respect to the Notes in
global form, or any successor entity thereto.

                                       9
<PAGE>

     "Debt to Adjusted Consolidated Cash Flow Ratio" means, as of any date of
determination, the ratio of:

          (1)  the Consolidated Indebtedness of the Company as of such date to

          (2)  the Adjusted Consolidated Cash Flow of the Company as of such
               date.

     "Default" means any event that is, or with the passage of time or the
giving of notice or both would be, an Event of Default.

     "Definitive Note" means a certificated Note registered in the name of the
Holder thereof and issued in accordance with Section 2.06 hereof, substantially
in the form of Exhibit A hereto except that such Note shall not bear the Global
Note Legend and shall not have the "Schedule of Exchanges of Interests in the
Global Note" attached thereto.

     "Depositary" means, with respect to the Notes issuable or issued in whole
or in part in global form, the Person specified in Section 2.03 hereof as the
Depositary with respect to the Notes, and any and all successors thereto
appointed as depositary hereunder and having become such pursuant to the
applicable provision of this Indenture.

     "Disqualified Stock" means any Capital Stock that, by its terms (or by the
terms of any security into which it is convertible or for which it is
exchangeable, in each case, at the option of the holder thereof), or upon the
happening of any event, matures or is mandatorily redeemable, pursuant to a
sinking fund obligation or otherwise, or redeemable at the option of the holder
thereof, in whole or in part, on or prior to the date that is 91 days after the
date on which the Notes mature; provided, however, that any Capital Stock that
would constitute Disqualified Stock solely because the holders thereof have the
right to require the Company to repurchase such Capital Stock upon the
occurrence of a Change of Control or an Asset Sale shall not constitute
Disqualified Stock if the terms of such Capital Stock provide that the Company
may not repurchase or redeem any such Capital Stock pursuant to such provisions
unless such repurchase or redemption complies with Section 4.07 hereof.

     "Eligible Indebtedness" means

          (1)  Indebtedness under the Credit Facilities, and

          (2)  any other Indebtedness other than:

               (a)  Indebtedness in the form of, or represented by, bonds or
                    other securities or any guarantee thereof; and

               (b)  Indebtedness that is, or may be, quoted, listed or purchased
                    and sold on any stock exchange, automated trading system or
                    over-the-counter or other securities market (including,
                    without prejudice to the generality of the foregoing, the
                    market for securities eligible for resale pursuant to Rule
                    144A).
<PAGE>

     "Equity Interests" means Capital Stock and all warrants, options or other
rights to acquire Capital Stock (but excluding any debt security that is
convertible into, or exchangeable for, Capital Stock).

     "Euroclear" means Euroclear Bank S.A./N.V., as operator of the Euroclear
system (or any successor securities clearing agency).

     "Exchange Act" means the Securities Exchange Act of 1934, as amended.

     "Exchange Note" means any Note issued in exchange for an Original Note or
Original Notes pursuant to the Exchange Offer or otherwise registered under the
Securities Act and any Note with respect to which the next preceding Predecessor
Note of such Note was an Exchange Note.

     "Exchange Offer" has the meaning set forth in the form of Note attached as
Exhibit A.

     "Exchange Registration Statement" has the meaning set forth in the form of
Note attached as Exhibit A.

     "Excepted Verestar Debt" means Indebtedness of Verestar and its
Subsidiaries at a time when Verestar and its Subsidiaries have Special Verestar
Status, which Indebtedness constitutes

          (1)  Capital Lease Obligations not constituting Indebtedness of the
               Company or its Restricted Subsidiaries,

          (2)  Acquired Debt not constituting Indebtedness of the Company or its
               Restricted Subsidiaries in an aggregate principal amount of up to
               $20.0 million at any one time outstanding,

          (3)  Indebtedness owed to the Company or its Restricted Subsidiaries,

          (4)  Indebtedness owed to Verestar or its Subsidiaries, or

          (5)  Indebtedness under a Credit Facility that also constitutes
               Indebtedness of the Company or its Restricted Subsidiaries (but
               not of any other Person).

     "Excepted Verestar Dividend" means a dividend or distribution on the
Company's Capital Stock consisting of common stock or similar Capital Stock of
Verestar at a time when Verestar and its Subsidiaries are not Restricted
Subsidiaries of the Company.

     "Excepted Verestar Sale" means an issue, sale or other disposition of
common stock or similar Voting Stock of Verestar at a time when it is a
Restricted Subsidiary of the Company, so long as after giving effect thereto
Verestar would remain a Subsidiary of the Company.

                                      11
<PAGE>

     "Excluded International Sale" means an issue, sale or other disposition of
Capital Stock of a Restricted Subsidiary of the Company the principal operations
of which are conducted, and the principal assets of which are located, outside
the United States, so long as after giving effect thereto such Restricted
Subsidiary would remain a Restricted Subsidiary of the Company.

     "Existing Indebtedness" means Indebtedness of the Company and its
Subsidiaries (other than Indebtedness under the Senior Credit Facility) in
existence on the Issue Date, until such amounts are repaid.

     "GAAP" means generally accepted accounting principles in the United States
set forth in the opinions and pronouncements of the Accounting Principles Board
of the American Institute of Certified Public Accountants and statements and
pronouncements of the Financial Accounting Standards Board or in such other
statements by such other entity as have been approved by a significant segment
of the accounting profession, which are in effect on the date hereof.

     "Global Note Legend" means the legend set forth in Section 2.06(f)(i),
which is required to be placed on all Global Notes issued under this Indenture.

     "Global Notes" means, the global Notes, substantially in the form of
Exhibit A hereto.

     "Government Securities" means direct obligations of, or obligations
guaranteed by, the United States of America, and the payment for which the
United States pledges its full faith and credit.

     "Guarantee" means a guarantee (other than by endorsement of negotiable
instruments for collection in the ordinary course of business), direct or
indirect, in any manner (including, without limitation, by way of a pledge of
assets or through letters of credit or reimbursement agreements in respect
thereof), of all or any part of any Indebtedness.

     "Hedging Obligations" means, with respect to any Person, the obligations of
such Person under:

          (1)  interest rate swap agreements, interest rate cap agreements and
               interest rate collar agreements; and

          (2)  other agreements or arrangements designed to protect such Person
               against fluctuations in interest rates or currency exchange
               rates.

     "Holder" means a Person in whose name a Note is registered.

     "Indebtedness" means, with respect to any Person, any indebtedness of such
Person, whether or not contingent, in respect of borrowed money or evidenced by
bonds, notes, debentures or similar instruments or letters of credit (or
reimbursement agreements in respect thereof) or banker's acceptances or
representing Capital Lease Obligations or the balance deferred and unpaid of the
purchase price of any property or representing any Hedging Obligations, except
any such balance that constitutes an accrued expense or trade payable, if and

                                      12
<PAGE>

to the extent any of the foregoing indebtedness (other than letters of credit
and Hedging Obligations) would appear as a liability upon a balance sheet of
such Person prepared in accordance with GAAP, as well as all Indebtedness of
others secured by a Lien on any asset of such Person whether or not such
Indebtedness is assumed by such Person (the amount of such Indebtedness as of
any date being deemed to be the lesser of the value of such property or assets
as of such date or the principal amount of such Indebtedness of such other
Person so secured) and, to the extent not otherwise included, the Guarantee by
such Person of any Indebtedness of any other Person. The amount of any
Indebtedness outstanding as of any date shall be:

          (1)  the accreted value thereof, in the case of any Indebtedness
               issued with original issue discount; and

          (2)  the principal amount thereof, together with any interest thereon
               that is more than 30 days past due, in the case of any other
               Indebtedness.

     "Indenture" means this Indenture, as amended or supplemented from time to
time.

     "Indirect Participant" means a Person who holds a beneficial interest in a
Global Note through a Participant.

     "Investment Grade Rating" means a rating equal to or higher than Baa3 (or
the equivalent) by Moody's and BBB- (or the equivalent) by S&P.

     "Investments" means, with respect to any Person, all investments by such
Person in other Persons (including Affiliates) in the forms of direct or
indirect loans (including guarantees of Indebtedness or other obligations),
advances or capital contributions (excluding commission, travel and similar
advances to officers and employees made in the ordinary course of business),
purchases or other acquisitions for consideration of Indebtedness, Equity
Interests or other securities, together with all items that are or would be
classified as investments on a balance sheet prepared in accordance with GAAP.
If the Company or any Restricted Subsidiary of the Company sells or otherwise
disposes of any Equity Interests of any direct or indirect Restricted Subsidiary
of the Company or a Restricted Subsidiary of the Company issues any of its
Equity Interests such that, in each case, after giving effect to any such sale,
disposition or issuance, such Person is no longer a Restricted Subsidiary of the
Company, the Company shall be deemed to have made an Investment on the date of
any such sale, disposition or issuance equal to the fair market value of the
Equity Interests of such Subsidiary not sold or disposed of in an amount
determined as provided in the final paragraph of Section 4.07 hereof.

     "Issue Date" means the date on which the Original Notes are first
authenticated and delivered under this Indenture.

     "Legal Holiday" means a Saturday, a Sunday or a day on which banking
institutions in The City of New York or at a place of payment are authorized by
law, regulation or executive order to remain closed. If a payment date is a
Legal Holiday at a place of payment, payment may be made at that place on the
next succeeding day that is not a Legal Holiday, and no interest shall accrue on
such payment for the intervening period.

                                      13
<PAGE>

     "Licenses" means, collectively, any telephone, microwave, radio
transmissions, personal communications or other license, authorization,
certificate of compliance, franchise, approval or permit, whether for the
construction, the ownership or the operation of any communications tower
facilities, granted or issued by the Federal Communications Commission (or other
similar or successor agency of the federal government administering the
Communications Act of 1934 or any similar or successor federal statute) and held
by the Company or any of its Restricted Subsidiaries.

     "Lien" means, with respect to any asset, any mortgage, lien, pledge,
charge, security interest or encumbrance of any kind in respect of such asset,
whether or not filed, recorded or otherwise perfected under applicable law
(including any conditional sale or other title retention agreement, any lease in
the nature thereof, any option or other agreement to sell or give a security
interest in and any filing of or agreement to give any financing statement under
the Uniform Commercial Code (or equivalent statutes) of any jurisdiction).

     "Moody's" means Moody's Investors Service, Inc. or any successor to the
rating agency business thereof.

     "Net Income" means, with respect to any Person, the net income (loss) of
such Person, determined in accordance with GAAP and before any reduction in
respect of preferred stock dividends, excluding, however:

          (1)  any gain or loss, together with any related provision for taxes
               on such gain or loss, realized in connection with:

               (a)  any Asset Sale (including, without limitation, dispositions
                    pursuant to sale and leaseback transactions); or

               (b)  the disposition of any securities by such Person or any of
                    its Restricted Subsidiaries or the extinguishment of any
                    Indebtedness of such Person or any of its Restricted
                    Subsidiaries; and

          (2)  any extraordinary gain or loss, together with any related
               provision for taxes on such extraordinary gain or loss.

     "Net Proceeds" means the aggregate cash proceeds received by the Company or
any of its Restricted Subsidiaries in respect of any Asset Sale (including,
without limitation, any cash received upon the sale or other disposition of any
non-cash consideration received in any Asset Sale), net of:

          (1)  the direct costs relating to such Asset Sale (including, without
               limitation, legal, accounting and investment banking fees, sales
               commissions and finders', brokers' or similar fees) and any
               relocation or severance expenses incurred as a result thereof;

                                      14
<PAGE>

          (2)  taxes paid or payable as a result thereof (after taking into
               account any available tax credits or deductions and any tax
               sharing arrangements);

          (3)  amounts required to be applied to the repayment of Indebtedness
               (other than Indebtedness under a Credit Facility) secured by a
               Lien on the asset or assets that were the subject of such Asset
               Sale;

          (4)  all distributions and other payments required to be made to
               minority interest holders in Restricted Subsidiaries as a result
               of such Asset Sale;

          (5)  the deduction of appropriate amounts provided by the seller as a
               reserve in accordance with GAAP against any liabilities
               associated with the assets disposed of in such Asset Sale and
               retained by the Company or any Restricted Subsidiary after such
               Asset Sale; and

          (6)  without duplication, any reserves that Board of Directors
               determines in good faith should be made in respect of the sale
               price of such asset or assets for post closing adjustments;

provided that in the case of any reversal of any reserve referred to in clause
(5) or (6) above, the amount so reversed shall be deemed to be Net Proceeds from
an Asset Sale as of the date of such reversal.

     "Non-Recourse Debt" means Indebtedness:

          (1)  as to which neither the Company nor any of its Restricted
               Subsidiaries:

               (a)  provides credit support of any kind (including any
                    undertaking, agreement or instrument that would constitute
                    Indebtedness); or

               (b)  is directly or indirectly liable (as a guarantor or
                    otherwise);

          (2)  no default with respect to which (including any rights that the
               holders thereof may have to take enforcement action against an
               Unrestricted Subsidiary) would permit (upon notice, lapse of time
               or both) any holder of any other Indebtedness of the Company or
               any of its Restricted Subsidiaries to declare a default on such
               other Indebtedness or cause the payment thereof to be accelerated
               or payable prior to its stated maturity; and

          (3)  as to which the lenders have been notified in writing that they
               will not have any recourse to the stock or assets of the Company
               or any of its Restricted Subsidiaries.

                                      15
<PAGE>

     "Non-Tower Cash Flow" means, as of any date of determination, the
Consolidated Cash Flow of the Company for the four most recent full fiscal
quarters ending immediately prior to such date for which internal financial
statements are available that is not included in Tower Cash Flow, all determined
on a consolidated basis and in accordance with GAAP. Non-Tower Cash Flow will
not include revenues derived from asset sales other than sales or other
dispositions of inventory in the ordinary course of business.

     "Notes" has the meaning assigned to it in the preamble to this Indenture
and includes the Exchange Notes and the Original Notes.

     "Obligations" means any principal, interest, penalties, fees,
indemnifications, reimbursements, damages and other liabilities payable under
the documentation governing any Indebtedness.

     "Offering" means the private offering of the Notes by the Company.

     "Offering Circular" means the Confidential Offering Circular, dated January
24, 2001, including the documents incorporated by reference therein, relating to
the private offering of the Original Notes.

     "Officer" means, with respect to any Person, the Chairman of the Board, the
Chief Executive Officer, the President, the Chief Operating Officer, the Chief
Financial Officer, the Treasurer, any Assistant Treasurer, the Controller, the
Secretary or any Vice-President of such Person.

     "Officers' Certificate" means a certificate signed on behalf of the Company
by two Officers of the Company, one of whom must be the principal executive
officer, the principal financial officer, the treasurer or the principal
accounting officer of the Company, that meets the requirements of Section 11.04
hereof.

     "Opinion of Counsel" means an opinion from legal counsel that meets the
requirements of Section 11.04 hereof. The counsel may be an employee of or
counsel to the Company or any Subsidiary of the Company.

     "Participant" means, with respect to the Depositary, Euroclear or
Clearstream, a Person who has an account with the Depositary, Euroclear or
Clearstream, respectively (and, with respect to DTC, shall include Euroclear and
Clearstream).

     "Permitted Business" means any business of the type conducted by the
Company or its Restricted Subsidiaries on the Issue Date and, at such time as
Verestar and its Subsidiaries become Restricted Subsidiaries, any business of
the type conducted by them on the Issue Date, and any other business related,
ancillary or complementary to any such business.

                                      16
<PAGE>

     "Permitted Investment" means:

          (1)  any Investment in the Company or in a Restricted Subsidiary of
               the Company;

          (2)  any Investment in Cash Equivalents;

          (3)  any Investment by the Company or any Restricted Subsidiary of the
               Company in a Person, if as a result of such Investment:

               (a)  such Person becomes a Restricted Subsidiary of the Company;
                    or

               (b)  such Person is merged, consolidated or amalgamated with or
                    into, or transfers or conveys substantially all of its
                    assets to, or is liquidated into, the Company or a
                    Restricted Subsidiary of the Company;

          (4)  any Investment by the Company or any Restricted Subsidiary of the
               Company that

               (a)  is in substance the acquisition of a class of Capital Stock
                    of a Restricted Subsidiary (the "Target") of the Company,

               (b)  increases the percentage of one or more classes of Capital
                    Stock of the Target beneficially owned by the Company and
                    its Restricted Subsidiaries,

               (c)  does not decrease the percentage of the total voting power
                    of shares of Capital Stock of the Target entitled (without
                    regard to the occurrence of any contingency) to vote in the
                    election of directors, managers or trustees of the Target
                    that is owned by the Company and its Restricted
                    Subsidiaries, and

               (d)  does not decrease the percentage of stockholders' equity
                    (including stock subject to mandatory redemption) of the
                    Target, as reflected on its most recent internal balance
                    sheet prepared in accordance with GAAP, available upon
                    liquidation of the Target to Capital Stock of the Target
                    owned by the Company and its Restricted Subsidiaries;

          (5)  any Investment made as a result of the receipt of non-cash
               consideration from an Asset Sale that was made pursuant to and in
               compliance with Section 4.10 hereof;

          (6)  any acquisition of assets solely in exchange for the issuance of
               Equity Interests (other than Disqualified Stock) of the Company;

                                      17
<PAGE>

          (7)  receivables created in the ordinary course of business;

          (8)  loans or advances to employees made in the ordinary course of
               business since the Issue Date not to exceed $5.0 million at any
               one time outstanding;

          (9)  securities and other assets received in settlement of trade debts
               or other claims arising in the ordinary course of business;

          (10) the Verestar Net Investment up to an aggregate of $100.00 million
               at any one time outstanding;

          (11) Investments since the Issue Date (other than Investments in
               Verestar or its subsidiaries) of up to an aggregate of $100.0
               million at any one time outstanding (each such Investment being
               measured as of the date made and without giving effect to
               subsequent changes in value); and

          (12) other Investments in Permitted Businesses since the Issue Date
               not to exceed an amount equal to $10.0 million plus 10% of the
               Company's Consolidated Tangible Assets at any one time
               outstanding (each such Investment being measured as of the date
               made and without giving effect to subsequent changes in value).

     "Permitted Liens" means:

          (1)  Liens securing Indebtedness of the Company under one or more
               Credit Facilities that was permitted by the terms hereof to be
               incurred;

          (2)  Liens securing any Indebtedness of any of the Company's
               Restricted Subsidiaries that was permitted by the terms hereof to
               be incurred;

          (3)  Liens in favor of the Company;

          (4)  Liens existing on the Issue Date and renewals and replacements
               thereof to the extent they secure Permitted Refinancing
               Indebtedness;

          (5)  Liens for taxes, assessments or governmental charges or claims
               that are not yet delinquent or that are being contested in good
               faith by appropriate proceedings promptly instituted and
               diligently concluded; provided that any reserve or other
               appropriate provision as shall be required in conformity with
               GAAP shall have been made therefor;

                                      18
<PAGE>

          (6)  Liens of carriers, warehousemen, mechanics, vendors (solely to
               the extent arising by operation of law), laborers and materialmen
               incurred in the ordinary course of business for sums not yet due
               or being diligently contested in good faith, if reserves or
               appropriate provisions shall have been made therefor;

          (7)  Liens incurred in the ordinary course of business in connection
               with worker's compensation and unemployment insurance, social
               security obligations, assessments or government charges which are
               not overdue for more than 60 days;

          (8)  Restrictions on the transfer of Licenses or assets of the Company
               or any of its Restricted Subsidiaries imposed by any of the
               Licenses as in effect on the Issue Date or imposed by the
               Communications Act of 1934, any similar or successor federal
               statute or the rules and regulations of the Federal
               Communications Commission (or other similar or successor agency
               of the federal government administering such Act or successor
               statute) thereunder, all as the same may be in effect from time
               to time;

          (9)  Liens arising by operation of law in favor of purchasers in
               connection with the sale of an asset; provided, however, that
               such Lien only encumbers the property being sold;

          (10) Liens to secure performance of statutory obligations, surety or
               appeal bonds, performance bonds, bids or tenders;

          (11) judgment Liens which do not result in an Event of Default;

          (12) Liens in connection with escrow deposits made in connection with
               any acquisition of assets;

          (13) Liens securing Indebtedness permitted to be incurred under
               clauses (3) and (6) of the second paragraph of Section 4.09
               hereof;

          (14) Easements, right-of-way, zoning restrictions, licenses or
               restrictions on use and other similar encumbrances on the use of
               real property that:

               (a)  are not incurred in connection with the borrowing of money
                    or the obtaining of advances or credit (other than trade
                    credit in the ordinary course of business); and

               (b)  do not in the aggregate materially detract from the value of
                    the property or materially impair the use thereof in the
                    operation of business by the Company and its Restricted
                    Subsidiaries;

                                      19
<PAGE>

          (15) Liens on property of the Company or a Restricted Subsidiary at
               the time the Company or Restricted Subsidiary acquired the
               property, including acquisition by means of a merger or
               consolidation with or into the Company or any Restricted
               Subsidiary, provided, however, that such Liens are not created,
               incurred or assumed in connection with or in contemplation of
               such acquisition, and provided further that such Liens may not
               extend to any other property owned by the Company or any
               Restricted Subsidiary; and

          (16) Liens securing Indebtedness in an aggregate principal amount at
               any time outstanding that, together with any Attributable Debt,
               does not exceed 10% of:

               (a)  Consolidated Tangible Assets, reduced by

               (b)  the amount of current liabilities (excluding current
                    maturities of long-term debt) of the Company and its
                    Restricted Subsidiaries, further reduced by

               (c)  appropriate adjustments on account of minority interests in
                    Restricted Subsidiaries of the Company held by Persons other
                    than the Company and its Restricted Subsidiaries,

               all as shown on the most recent internal consolidated balance
               sheet of the Company and such Restricted Subsidiaries calculated
               on a consolidated basis in accordance with GAAP.

     "Permitted Refinancing Indebtedness" means any Indebtedness of the Company
or any of its Restricted Subsidiaries issued in exchange for, or the net
proceeds of which are used to extend, refinance, renew, replace, defease or
refund, other Indebtedness of the Company or any of its Restricted Subsidiaries
(other than intercompany Indebtedness); provided that:

          (1)  the principal amount (or initial accreted value, if applicable)
               of such Permitted Refinancing Indebtedness does not exceed the
               principal amount of (or accreted value, if applicable), plus
               accrued interest on, the Indebtedness so extended, refinanced,
               renewed, replaced, defeased or refunded (plus the amount of
               expenses and prepayment premiums incurred in connection
               therewith);

          (2)  such Permitted Refinancing Indebtedness has a final maturity date
               not earlier than the final maturity date of, and has a Weighted
               Average Life to Maturity equal to or greater than the Weighted
               Average Life to Maturity of, the Indebtedness being extended,
               refinanced, renewed, replaced, defeased or refunded;

                                      20
<PAGE>

          (3)  if the Indebtedness being extended, refinanced, renewed,
               replaced, defeased or refunded is subordinated in right of
               payment to the Notes, such Permitted Refinancing Indebtedness is
               subordinated in right of payment to the Notes on terms at least
               as favorable to the Holders of Notes as those contained in the
               documentation governing the Indebtedness being extended,
               refinanced, renewed, replaced, defeased or refunded; and

          (4)  such Indebtedness is incurred either by the Company or by the
               Restricted Subsidiary who is the obligor on the Indebtedness
               being extended, refinanced, renewed, replaced, defeased or
               refunded.

     "Person" means any individual, corporation, partnership, limited liability
company, joint venture, association, joint-stock company, trust, unincorporated
organization or government or agency or political subdivision thereof (including
any subdivision or ongoing business of any such entity or substantially all of
the assets of any such entity, subdivision or business).

     "Predecessor Note" of any particular Note means every previous Note issued
before, and evidencing all or a portion of the same debt as that evidenced by,
such particular Note; and, for the purposes of this definition, any Note
authenticated and delivered under Section 2.07 in exchange for or in lieu of a
mutilated, destroyed, lost or stolen Note shall be deemed to evidence the same
debt as the mutilated, destroyed, lost or stolen Note.

     "Principal" means Steven B. Dodge and any Related Party of Steven B. Dodge.

     "Public Equity Offering" means an underwritten primary public offering of
common stock of the Company pursuant to an effective registration statement
under the Securities Act.

     "Purchase Agreement" means the Purchase Agreement, dated January 24, 2001,
among the Company and the Purchasers, as such agreement may be amended from time
to time.

     "Purchasers" means Donaldson, Lufkin, Jenrette Securities Corporation (an
affiliate of Credit Suisse First Boston Corporation), Salomon Smith Barney Inc.,
Deutsche Banc Alex. Brown Inc., Goldman, Sachs & Co., Lehman Brothers Inc., TD
Securities (USA) Inc., BNY Capital Markets, Inc., Chase Securities Inc., RBC
Dominion Securities Corporation, Scotia Capital (USA) Inc., Banc of America
Securities LLC, BMO Nesbitt Burns Inc., Credit Lyonnais Securities (USA) Inc.,
McDonald Investments Inc. and Thomas Weisel Partners LLC.

     "Qualified Proceeds" means assets that are used or useful in, or Capital
Stock of any Person engaged in, a Permitted Business.

     "Rating Agencies" mean Moody's and S&P.

     "Registered Notes" means the Exchange Notes and all other Notes sold or
otherwise disposed of pursuant to an effective registration statement under the
Securities Act, together with their respective Successor Notes.

                                      21
<PAGE>

     "Registration Default" has the meaning set forth in the form of Note
attached as Exhibit A.

     "Registration Rights Agreement" means the Registration Rights Agreement
among the Company and the Purchasers, dated the Issue Date, as the same may be
amended, supplemented or otherwise modified from time to time in accordance with
its terms.

     "Regular Record Date" has the meaning set forth in the form of Note
attached as Exhibit A.

     "Regulation S" means Regulation S under the Securities Act (or any
successor provision), as it may be amended from time to time.

     "Regulation S Certificate" means a certificate substantially in the form
set forth in Exhibit D.

     "Regulation S Global Note" has the meaning specified in Section 2.01(d).

     "Regulation S Legend" means a legend substantially in the form of the
legend required in the form of Note attached as Exhibit A to be placed upon each
Regulation S Note.

     "Regulation S Notes" means all Notes required pursuant to Section
2.06(f)(ii) to bear a Regulation S Legend. Such term includes the Regulation S
Global Note.

     "Related Party" with respect to the Principal means:

          (1)  any Person that is a Subsidiary of the Principal; or

          (2)  any trust, corporation, partnership, limited liability company or
               other entity, the beneficiaries, stockholders, members, partners,
               owners or Persons beneficially holding an over-50% controlling
               interest of which consist of the Principal and/or such other
               Persons referred to in the immediately preceding clause (1).

     "Resale Registration Statement" has the meaning set forth in the form of
Note attached as Exhibit A.

     "Responsible Officer" with respect to the Trustee, means any officer within
the Corporate Trust Administration of the Trustee (or any successor group of the
Trustee) or any other officer of the Trustee customarily performing functions
similar to those performed by any of the above designated officers and also
means, with respect to a particular corporate trust matter, any other officer to
whom such matter is referred because of his knowledge of and familiarity with
the particular subject and who shall have direct responsibility for the
administration of its Indenture.

     "Restricted Global Note" has the meaning specified in Section 2.01(d).

     "Restricted Investment" means an Investment other than a Permitted
Investment.

                                      22
<PAGE>

     "Restricted Notes" means all Notes required pursuant to Section 2.06(f)(ii)
to bear any Restricted Notes Legend. Such term includes the Restricted Global
Note.

     "Restricted Notes Certificate" means a certificate substantially in the
form set forth in Exhibit E.

     "Restricted Notes Legend" means, collectively, the legends substantially in
the forms of the legends required in the form of Note attached as Exhibit A to
be placed upon each Restricted Note.

     "Restricted Period" means the period of 41 consecutive days beginning on
and including the later of (i) the day on which Notes are first offered to
persons other than distributors (as defined in Regulation S) in reliance on
Regulation S and (ii) the Issue Date.

     "Restricted Subsidiary" of a Person means any Subsidiary of the referent
Person that is not an Unrestricted Subsidiary.

     "Rule 144A" means Rule 144A under the Securities Act (or any successor
provision), as such Rule 144A may be amended from time to time.

     "Rule 144A Notes" means the Notes purchased by the Purchasers from the
Company pursuant to the Purchase Agreement, other than the Regulation S Notes.

     "S&P" means Standard & Poor's Ratings Service or any successor to the
rating agency business thereof.

     "SEC" means the Securities and Exchange Commission.

     "Securities Act" means the Securities Act of 1933, as amended.

     "Securities Act Legend" means a Restricted Notes Legend or a Regulation S
Legend.

     "Senior Credit Facility" means that certain Amended and Restated Loan
Agreement, dated as of January 6, 2000, by and among The Toronto Dominion Bank,
New York Branch, as Issuing Bank, Toronto Dominion (Texas), Inc., as
Administrative Agent, the several Lenders and other agents party thereto and
American Tower, L.P., American Towers, Inc. and ATC Teleports, Inc., as
borrowers, including any related notes, guarantees, collateral documents,
instruments and agreements executed in connection therewith, and in each case as
amended, modified, renewed, refunded, replaced or refinanced from time to time.

     "Significant Subsidiary" means, with respect to any Person, any Restricted
Subsidiary of such Person that would be a "significant subsidiary" of such
Person as defined in Article 1, Rule 1-02 of Regulation S-X, promulgated
pursuant to the Act, as such Regulation is in effect on the date hereof, except
that all references to "10 percent" in Rule 1-02(w)(1), (2) and (3) shall mean
"5 percent" and that all Unrestricted Subsidiaries of the Company shall be
excluded from all calculations under Rule 1-02(w).

                                      23
<PAGE>

     "Special Verestar Status" means that Verestar and its Subsidiaries are not
Restricted Subsidiaries of the Company, that none has previously been a
Restricted Subsidiary of the Company, and that Verestar or its Subsidiaries have
since the Issue Date continuously had outstanding Indebtedness under clause (5)
of the definition of "Excepted Verestar Debt".

     "Stated Maturity" means, with respect to any installment of interest or
principal on any series of Indebtedness, the date on which such payment of
interest or principal was scheduled to be paid in the original documentation
governing such Indebtedness, and shall not include any contingent obligations to
repay, redeem or repurchase any such interest or principal prior to the date
originally scheduled for the payment thereof.

     "Step-Down Date" has the meaning set forth in the form of Note attached as
Exhibit A.

     "Step-Up" has the meaning set forth in the form of Note attached as Exhibit
A.

     "Strategic Equity Investment" means a cash contribution to the common
equity capital of the Company or a purchase from the Company of common Equity
Interests (other than Disqualified Stock), in either case by or from a Strategic
Equity Investor and for aggregate cash consideration of at least $50.0 million.

     "Strategic Equity Investor" means a Person engaged in a Permitted Business
whose Total Equity Market Capitalization exceeds $1.0 billion.

     "Subsidiary" means, with respect to any Person:

          (1)  any corporation, limited liability company, association or other
               business entity of which more than 50% of the total voting power
               of shares of Capital Stock entitled (without regard to the
               occurrence of any contingency) to vote in the election of
               directors, managers or trustees thereof is at the time owned or
               controlled, directly or indirectly, by such Person or one or more
               of the other Subsidiaries of that Person (or a combination
               thereof); and

          (2)  any partnership:

               (a)  the sole general partner or the managing general partner of
                    which is such Person or a Subsidiary of such Person; or

               (b)  the only general partners of which are such Person or of one
                    or more Subsidiaries of such Person (or any combination
                    thereof).

     "Successor Note" of any particular Note means every Note issued after, and
evidencing all or a portion of the same debt as that evidenced by, such
particular Note; and, for purposes of this definition, any Note authenticated
and delivered under Section 2.07 in exchange for or in lieu of a mutilated,
destroyed, lost or stolen Note shall be deemed to evidence the same debt as the
mutilated, destroyed, lost or stolen Note.

                                      24
<PAGE>

     "Surplus Asset Sale" means (i) an Asset Sale of communications transmission
towers that were acquired from AT&T Corporation and its Affiliates, have an
aggregate book value on the Company's GAAP balance sheet at September 30, 2000
and at the Issue Date of not more than $20.0 million, and are shown on the GAAP
accounting records of the Company and its Restricted Subsidiaries at September
30, 2000 and at the Issue Date as being held for disposal, and (ii) Asset Sales
in any one-year period for aggregate net proceeds of up to $5.0 million.

     "Tax Sharing Agreement" means the Tax Sharing Agreement, dated as of
January 1, 2000, among the Company, Verestar and any other Subsidiaries of the
Company or Verestar, as in effect on the Issue Date.

     "Teleports Business" means the business of providing domestic and
international satellite and internet protocol network transmission services.

     "Teleports Company" means Verestar and its Subsidiaries, or any successor
Person and that Person's Subsidiaries through which the Company conducts the
Teleports Business.

     "TIA" means the Trust Indenture Act of 1939 (15 U.S.C. ss.ss. 77aaa-77bbbb)
as in effect on the date on which this Indenture is qualified under the TIA.

     "Total Equity Market Capitalization" of any Person means, as of any date of
determination, the sum of:

          (1)  the product of:

               (a)  the aggregate number of outstanding primary shares of common
                    stock of such Person on such date (which shall not include
                    any options or warrants on, or securities convertible or
                    exchangeable into, shares of common stock of such person);
                    multiplied by

               (b)  the average closing price of such common stock listed on a
                    national securities exchange or the Nasdaq National Market
                    System over the 20 consecutive business days immediately
                    preceding such date; plus

          (2)  the liquidation value of any outstanding shares of preferred
               stock of such Person on such date.

     "Tower Asset Exchange" means any transaction in which the Company or one or
more of its Restricted Subsidiaries exchanges assets for, or issues its Capital
Stock in exchange for, Tower Assets and/or cash or Cash Equivalents where the
fair market value (evidenced by a resolution of the Board of Directors set forth
in an Officers' Certificate delivered to the Trustee) of the Tower Assets and
cash or Cash Equivalents received by the Company and its Restricted Subsidiaries
in such exchange is at least equal to the fair market value of the assets
disposed of, or the Capital Stock issued, in such exchange.

                                      25
<PAGE>

     "Tower Assets" means wireless transmission or broadcast towers and related
assets that are located on the site of a wireless transmission or broadcast
tower.

     "Tower Cash Flow" means, for any period, the Consolidated Cash Flow of the
Company and its Restricted Subsidiaries for such period that is directly
attributable (including related expenses) to (i) site rental revenue or license
fees (including space reservation payments) paid to lease, sublease or retain
space on communication sites owned or leased by the Company or its Restricted
Subsidiaries, (ii) fees paid to the Company or its Restricted Subsidiaries for
management of communications sites and (iii) real estate lease and similar
payments (whether or not related to communications sites) paid to the Company or
its Restricted Subsidiaries to the extent included in the same operating segment
for GAAP reporting purposes as site rental revenue, all determined on a
consolidated basis and in accordance with GAAP. Tower Cash Flow will not include
revenue or expenses attributable to non-site rental services provided by the
Company or any of its Restricted Subsidiaries to lessees of communication sites
or revenues derived from the sale of assets.

     "Treasury Rate" means, as of any redemption date in respect of the Notes,
the yield to maturity as of such redemption date of United States Treasury
securities with a constant maturity (as compiled and published in the most
recent Federal Reserve Statistical Release H.15(519) that has become publicly
available at least two business days prior to the redemption date (or, if such
Statistical Release is no longer published, any publicly available source of
similar market data)) most nearly equal to the period from the redemption date
to February 1, 2005; provided, however, that if the period from the redemption
date to February 1, 2005 is less than one year, the weekly average yield on
actually traded United States Treasury securities adjusted to a constant
maturity of one year shall be used.

     "Trustee" means the party named as such above until a successor replaces it
in accordance with the applicable provisions of this Indenture and thereafter
means the successor serving hereunder.

     "Unrestricted Notes Certificate" means a certificate substantially in the
form set forth in Exhibit F.

     "Unrestricted Subsidiary" means (i) on and after the Issue Date, Verestar
and all of its Subsidiaries, until such time as they become Restricted
Subsidiaries pursuant to a board resolution or otherwise pursuant to Section
4.07 and (ii) any other Subsidiary of the Company that is designated by the
Board of Directors as an Unrestricted Subsidiary, on or after the Issue Date,
pursuant to a board resolution; but only to the extent that, other than pursuant
to Excepted Verestar Debt, such Subsidiary:

          (1)  has no Indebtedness to any Person other than

               (a)  Non-Recourse Debt, or

               (b)  Indebtedness owed to the Company or its Restricted
                    Subsidiaries;

                                      26
<PAGE>

          (2)  is not party to any agreement, contract, arrangement or
               understanding with the Company or any Restricted Subsidiary of
               the Company unless the terms of any such agreement, contract,
               arrangement or understanding are no less favorable to the Company
               or such Restricted Subsidiary than those that might be obtained
               at the time from Persons who are not Affiliates of the Company;

          (3)  is a Person with respect to which neither the Company nor any of
               its Restricted Subsidiaries has any direct or indirect
               obligation:

               (a)  to subscribe for additional Equity Interests; or

               (b)  to maintain or preserve such Person's financial condition or
                    to cause such Person to achieve any specified levels of
                    operating results;

          (4)  has not guaranteed or otherwise directly or indirectly provided
               credit support for any Indebtedness of the Company or any of its
               Restricted Subsidiaries; and

          (5)  if such Subsidiary is Verestar or one of its Subsidiaries, is a
               Subsidiary through which the Company conducts the Teleports
               Business.

     Any such designation by the Board of Directors shall be evidenced to the
Trustee by filing with the trustee a certified copy of the board resolution
giving effect to such designation and an Officers' Certificate certifying that
such designation complied with the foregoing conditions and was permitted by
Section 4.07 hereof. If, at any time, any Unrestricted Subsidiary would fail to
meet the foregoing requirements as an Unrestricted Subsidiary, it shall
thereafter cease to be an Unrestricted Subsidiary for purposes of this
Indenture, and any Indebtedness of that Subsidiary shall be deemed to be
incurred by a Restricted Subsidiary of the Company as of such date (and, if such
Indebtedness is not permitted to be incurred as of such date under Section 4.09
hereof, the Company shall be in default of Section 4.09 hereof).

     The Board of Directors may at any time designate any Unrestricted
Subsidiary to be a Restricted Subsidiary; provided that the designation shall be
deemed to be an incurrence of Indebtedness by a Restricted Subsidiary of the
Company of any outstanding Indebtedness of such Unrestricted Subsidiary and the
designation shall only be permitted if

          (1)  such Indebtedness is permitted under Section 4.09 hereof,
               calculated on a pro forma basis as if such designation had
               occurred at the beginning of the four-quarter reference period;
               and

          (2)  no Default would occur or be in existence following such
               designation.

                                      27
<PAGE>

     If while Verestar or any of its Subsidiaries has Special Verestar Status,
the Verestar Net Investment shall exceed an aggregate of $100.0 million at any
one time outstanding, Verestar and its Subsidiaries shall thereafter cease to be
Unrestricted Subsidiaries for purposes of this Indenture, and any Indebtedness
of Verestar and its Subsidiaries shall be deemed to be incurred by a Restricted
Subsidiary of the Company as of such date (it being noted that Excepted Verestar
Debt shall be deemed to have been permitted to be incurred by clause (11) of the
second paragraph of Section 4.09 to the extent not otherwise permitted).

     "Verestar" means Verestar, Inc. (formerly ATC Teleports Inc.), a Delaware
corporation.

     "Verestar Net Investment" means the Investment of the Company and its
Restricted Subsidiaries since the Issue Date in Verestar and its Subsidiaries,
each such Investment being measured as of the date made and without giving
effect to subsequent changes in value, but excluding (a) any Investment made
with the net cash proceeds of a substantially concurrent sale after the Issue
Date by the Company of its Equity Interests (other than Disqualified Stock), (b)
any transaction resulting in the acquisition or receipt (whether by merger,
capital contribution or otherwise) by Verestar or its Subsidiaries of assets and
accompanied by the substantially concurrent issuance after the Issue Date by the
Company of its Equity Interests (other than Disqualified Stock) having a fair
market value, as determined in good faith by the Board of Directors, equal to
the fair market value of those assets, or (c) any Restricted Investment in
Verestar or its Subsidiaries that was made in compliance with Section 4.07
hereof. The receipt by Verestar or its Subsidiaries of proceeds from the
incurrence of Indebtedness under a Credit Facility described in clause (5) of
the definition of "Excepted Verestar Debt" while they have Special Verestar
Status shall be treated as an Investment by the Company in Verestar or such
Subsidiaries in an amount equal to such proceeds. The amount of any Investment
in Verestar and its Subsidiaries shall not include interest accrued on loans or
advances to Verestar or its Subsidiaries, but payment of such interest in cash
shall be considered, at the Company's election (but only to the extent not
otherwise included in Consolidated Net Income of the Company), either a
reduction of the Investment in Verestar or a distribution from an Unrestricted
Subsidiary for purposes of clause (3)(e) of the first paragraph of Section 4.07
hereof.

     "U.S. Person" means a U.S. person as defined in Rule 902(o) under the
Securities Act.

     "Voting Stock" of any Person as of any date means the Capital Stock of such
Person that is at the time entitled to vote in the election of the board of
directors or equivalent of such Person.

     "Weighted Average Life to Maturity" means, when applied to any Indebtedness
at any date, the number of years obtained by dividing:

          (1)  the sum of the products obtained by multiplying :

               (a)  the amount of each then remaining installment, sinking fund,
                    serial maturity or other required payments of principal,
                    including payment at final maturity, in respect thereof; by

                                      28
<PAGE>

               (b)  the number of years (calculated to the nearest one-twelfth)
                    that will elapse between such date and the making of such
                    payment; by

          (2)  the then outstanding principal amount of such Indebtedness.

     "Wholly Owned Restricted Subsidiary" of any Person means a Restricted
Subsidiary of such Person all of the outstanding Capital Stock or other
ownership interests of which (other than directors' qualifying shares) shall at
the time be owned by such Person or by one or more Wholly Owned Restricted
Subsidiaries of such Person or by such Person and one or more Wholly Owned
Restricted Subsidiaries of such Person.

     Section 1.02. Other Definitions.

          Term                                             Defined in Section
          ----                                             ------------------

          "Affiliate Transaction"................................. 4.11
          "Asset Sale Offer"...................................... 3.09
          "Authentication Order".................................. 2.02
          "Change of Control Offer"............................... 4.14
          "Change of Control Payment"............................. 4.14
          "Change of Control Payment Date"........................ 4.14
          "Covenant Defeasance"................................... 8.03
          "DTC"................................................... 2.03
          "Event of Default"...................................... 6.01
          "Excess Proceeds"....................................... 4.10
          "Guarantor"............................................. 10.01
          "incur"................................................. 4.09
          "Legal Defeasance"...................................... 8.02
          "Note Guarantee"........................................ 4.17
          "Offer Amount".......................................... 3.09
          "Offer Period".......................................... 3.09
          "Original Notes"........................................ 2.02
          "Paying Agent".......................................... 2.03
          "Payment Default"....................................... 6.01
          "Permitted Debt"........................................ 4.09
          "Purchase Date"......................................... 3.09
          "Registrar"............................................. 2.03
          "Restricted Payments"................................... 4.07
          "Suspended Covenants"................................... 4.18

     Section 1.03. Incorporation by Reference of Trust Indenture Act.

     Whenever this Indenture refers to a provision of the TIA, the provision is
incorporated by reference in and made a part of this Indenture.

                                      29
<PAGE>

     The following TIA terms used in this Indenture have the following meanings:

     "indenture securities" means the Notes;
     "indenture security Holder" means a Holder of a Note;
     "indenture to be qualified" means this Indenture;
     "indenture trustee" or "institutional trustee" means the Trustee; and
     "obligor" on the Notes means the Company and any successor obligor upon the
     Notes.

     All other terms used in this Indenture that are defined by the TIA, defined
by the TIA's reference to another statute or defined by SEC rule under the TIA
have the meanings so assigned to them.

     Section 1.04. Rules of Construction.

     Unless the context otherwise requires:

     (a) a term has the meaning assigned to it;

     (b) an accounting term not otherwise defined has the meaning assigned to it
in accordance with GAAP;

     (c) "or" is not exclusive;

     (d) words in the singular include the plural, and in the plural include the
singular;

     (e) provisions apply to successive events and transactions; and

     (f) references to sections of or rules under the Securities Act shall be
deemed to include substitute, replacement or successor sections or rules adopted
by the SEC from time to time.

                                    ARTICLE 2

                                    THE NOTES

     Section 2.01. Form and Dating.

     (a) General. The Notes and the Trustee's certificate of authentication
shall be substantially in the form of Exhibit A hereto. The Notes may have
notations, legends or endorsements required by law, stock exchange rule or
usage. Each Note shall be dated the date of its authentication. The Notes shall
be in denominations of $1,000 and integral multiples thereof.

                                      30
<PAGE>

     The Notes may consist of Original Notes and/or Exchange Notes, which shall
rank pari passu in right of payment with each other and with all other existing
and future senior unsecured obligations of the Company. Unless the context
otherwise requires, Original Notes and Exchange Notes shall be considered
collectively to be a single class for all purposes of this Indenture, including
without limitation waivers, amendments, redemptions and Asset Sale Offers.

     The terms and provisions contained in the Notes shall constitute, and are
hereby expressly made, a part of this Indenture and the Company and the Trustee,
by their execution and delivery of this Indenture, expressly agree to such terms
and provisions and to be bound thereby. However, to the extent any provision of
any Note conflicts with the express provisions of this Indenture, the provisions
of this Indenture shall govern and be controlling.

     (b) Global Notes. Notes issued in global form shall be substantially in the
form of Exhibit A attached hereto (including the Global Note Legend thereon and
the "Schedule of Exchanges of Interests in the Global Note" attached thereto).
Notes issued in definitive form shall be substantially in the form of Exhibit A
attached hereto (but without the Global Note Legend thereon and without the
"Schedule of Exchanges of Interests in the Global Note" attached thereto).

     Each Global Note shall represent such of the outstanding Notes as shall be
specified therein and each shall provide that it shall represent the aggregate
principal amount of outstanding Notes from time to time endorsed thereon and
that the aggregate principal amount of outstanding Notes represented thereby may
from time to time be reduced or increased, as appropriate, to reflect exchanges,
redemptions, repurchases and transfers of interests. Any endorsement of a Global
Note to reflect the amount of any increase or decrease in the aggregate
principal amount of outstanding Notes represented thereby shall be made by the
Trustee or the Custodian, at the direction of the Trustee, in accordance with
instructions given by the Holder thereof as required by Section 2.06 hereof.

     (c) Euroclear and Clearstream Procedures Applicable. The provisions of the
"Operating Procedures of the Euroclear System" and "Terms and Conditions
Governing Use of Euroclear" and the "General Terms and Conditions of
Clearstream" and "Customer Handbook" of Clearstream shall be applicable to
transfers of beneficial interests in Global Notes that are held by Participants
through Euroclear or Clearstream.

     (d) Restricted and Regulation S Global Notes. Upon their original issuance,
Rule 144A Notes shall be issued in the form of one or more Global Notes
registered in the name of the Depositary or its nominee and deposited with the
Trustee, as Custodian for the Depositary, for credit by the Depositary to the
respective accounts of beneficial owners of the Notes represented thereby (or
such other accounts as they may direct). Such Global Notes, together with their
Successor Notes which are Global Notes other than the Regulation S Global Notes,
are collectively herein called the "Restricted Global Note".

                                      31
<PAGE>

     Upon their original issuance, Regulation S Notes shall be issued in the
form of one or more Global Notes registered in the name of the Depositary, or
its nominee and deposited with the Trustee, as Custodian for the Depositary, for
credit to the respective accounts of the beneficial owners of the Notes
represented thereby (or such other accounts as they may direct), provided that
upon such deposit all such Notes shall be credited to or through accounts
maintained at the Depositary by or on behalf of Euroclear or Clearsteam. Such
Global Notes, together with their Successor Notes which are Global Notes other
than the Restricted Global Note, are collectively herein called the "Regulation
S Global Note".

     Section 2.02. Execution and Authentication.

     Two Officers shall sign the Notes for the Company by manual or facsimile
signature.

     If an Officer whose signature is on a Note no longer holds that office at
the time a Note is authenticated, the Note shall nevertheless be valid.

     A Note shall not be valid until authenticated by the manual signature of
the Trustee. The signature shall be conclusive evidence that the Note has been
authenticated under this Indenture.

     The Trustee shall, upon a written order of the Company signed by two
Officers (an "Authentication Order"), authenticate Notes for original issue on
the Issue Date in an aggregate principal amount not to exceed $1.0 billion (the
"Original Notes"). The aggregate principal amount of Notes (including Exchange
Notes) outstanding at any time may not exceed the aggregate principal amount
stated in paragraph 4 of the Notes except as provided in Section 2.08 hereof.
Notes shall be dated the date of their authentication.

     At any time and from time to time after the execution and delivery of this
Indenture and after the effectiveness of a Registration Statement under the
Securities Act with respect thereto, the Company may deliver Exchange Notes
executed by the Company to the Trustee for authentication, together with a
Company Order for the authentication and delivery of such Exchange Notes and a
like principal amount of Original Notes for cancellation in accordance with
Section 2.11 of this Indenture, and the Trustee in accordance with the Company
Order shall authenticate and deliver such Notes. In authenticating such Exchange
Notes, and accepting the additional responsibilities under this Indenture in
relation to such Notes, the Trustee shall be entitled to receive, and (subject
to Section 7.01) shall be fully protected in relying upon, an Opinion of Counsel
stating,

          (i)  that such Exchange Notes have been duly and validly issued in
               accordance with the terms of this Indenture, and are entitled to
               all the rights and benefits set forth herein; and

          (ii) that the issuance of the Exchange Notes in exchange for the
               Original Notes has been effected in compliance with the
               Securities Act.

                                      32
<PAGE>

     The Trustee may appoint an authenticating agent acceptable to the Company
to authenticate Notes. An authenticating agent may authenticate Notes whenever
the Trustee may do so. Each reference in this Indenture to authentication by the
Trustee includes authentication by such agent. An authenticating agent has the
same rights as an Agent to deal with Holders or an Affiliate of the Company.

     Section 2.03. Registrar and Paying Agent.

     The Company shall maintain an office or agency where Notes may be presented
for registration of transfer or for exchange ("Registrar") and an office or
agency where Notes may be presented for payment ("Paying Agent"). The Registrar
shall keep a register of the Notes and of their transfer and exchange. The
Company may appoint one or more co-registrars and one or more additional paying
agents. The term "Registrar" includes any co-registrar and the term "Paying
Agent" includes any additional paying agent. The Company may change any Paying
Agent or Registrar without notice to any Holder. The Company shall promptly
notify the Trustee in writing of the name and address of any Agent not a party
to this Indenture. If the Company fails to appoint or maintain another entity as
Registrar or Paying Agent, the Trustee shall act as such. The Company or any of
its Subsidiaries may act as Paying Agent or Registrar.

     The Company initially appoints The Depository Trust Company ("DTC") to act
as Depositary with respect to the Global Notes.

     The Company initially appoints the Trustee to act as the Registrar and
Paying Agent and to act as Custodian with respect to the Global Notes.

     Section 2.04. Paying Agent to Hold Money in Trust.

     The Company shall require each Paying Agent other than the Trustee to agree
in writing that the Paying Agent will hold in trust for the benefit of the
Holders or the Trustee all money held by the Paying Agent for the payment of
principal of, or premium, if any, or interest on the Notes, and will notify the
Trustee of any default by the Company in making any such payment. While any such
default continues, the Trustee may require a Paying Agent to pay all money held
by it to the Trustee. The Company at any time may require a Paying Agent to pay
all money held by it to the Trustee. Upon payment over to the Trustee, the
Paying Agent (if other than the Company or a Subsidiary) shall have no further
liability for the money. If the Company or a Subsidiary acts as Paying Agent, it
shall segregate and hold in a separate trust fund for the benefit of the Holders
all money held by it as Paying Agent. Upon any bankruptcy or reorganization
proceedings relating to the Company, the Trustee shall serve as Paying Agent for
the Notes.

     Section 2.05. Holder Lists.

     The Trustee shall preserve in as current a form as is reasonably
practicable the most recent list available to it of the names and addresses of
all Holders and shall otherwise comply with TIA ss. 312(a). If the Trustee is
not the Registrar, the Company shall furnish to the Trustee at least seven
Business Days before each interest payment date and at such other times as the

                                      33
<PAGE>

Trustee may request in writing, a list in such form and as of such date as the
Trustee may reasonably require of the names and addresses of the Holders of
Notes, and the Company shall otherwise comply with TIA ss. 312(a).

     Section 2.06. Transfer and Exchange.

     (a) Transfer and Exchange of Global Notes. A Global Note may not be
transferred as a whole except by the Depositary to a nominee of the Depositary,
by a nominee of the Depositary to the Depositary or to another nominee of the
Depositary, or by the Depositary or any such nominee to a successor Depositary
or a nominee of such successor Depositary. All Global Notes will be exchanged by
the Company for Definitive Notes if (i) the Company delivers to the Trustee
notice from the Depositary that it is unwilling or unable to continue to act as
Depositary or that it is no longer a clearing agency registered under the
Exchange Act and, in either case, a successor Depositary is not appointed by the
Company within 120 days after the date of such notice from the Depositary, (ii)
the Company in its sole discretion determines that the Global Notes (in whole
but not in part) should be exchanged for Definitive Notes and delivers a written
notice to such effect to the Trustee, or (iii) upon request of a Holder if there
shall have occurred and be continuing an Event of Default. Upon the occurrence
of any of the preceding events in (i), (ii) or (iii) above, Definitive Notes
shall be issued in such names as the Depositary shall instruct the Trustee.
Global Notes also may be exchanged or replaced, in whole or in part, as provided
in Sections 2.07 and 2.10 hereof. Every Note authenticated and delivered in
exchange for, or in lieu of, a Global Note or any portion thereof, pursuant to
this Section 2.06, or Section 2.07 or 2.10 hereof, shall be authenticated and
delivered in the form of, and shall be, a Global Note. A Global Note may not be
exchanged for another Note other than as provided in this Section 2.06(a);
however, beneficial interests in a Global Note may be transferred and exchanged
as provided in Section 2.06(b), (c) or (f) hereof.

      (b) Transfer and Exchange of Beneficial Interests in the Global Notes. The
transfer and exchange of beneficial interests in the Global Notes shall be
effected through the Depositary, in accordance with the provisions of this
Indenture and the Applicable Procedures. Transfers of beneficial interests in
the Global Notes also shall require compliance with either subparagraph (i) or
(ii) below, as applicable, as well as one or more of the other following
subparagraphs, as applicable:

            (i)   Transfer of Beneficial Interests in the Same Global Note.
                  Beneficial interests in any Global Note may be transferred to
                  Persons who take delivery thereof in the form of a beneficial
                  interest in the same Global Note. No written orders or
                  instructions shall be required to be delivered to the
                  Registrar to effect the transfers described in this Section
                  2.06(b)(i).

            (ii)  All Other Transfers and Exchanges of Beneficial Interests in
                  Global Notes. In connection with all transfers and exchanges
                  of beneficial interests that are not subject to Section
                  2.06(b)(i) above, the transferor of such beneficial interest
                  must deliver to the Registrar either (A) (1) a written order
                  from a Participant or an Indirect Participant given to the

                                      34
<PAGE>

                  Depositary in accordance with the Applicable Procedures
                  directing the Depositary to credit or cause to be credited a
                  beneficial interest in another Global Note in an amount equal
                  to the beneficial interest to be transferred or exchanged and
                  (2) instructions given in accordance with the Applicable
                  Procedures containing information regarding the Participant
                  account to be credited with such increase or (B) (1) a written
                  order from a Participant or an Indirect Participant given to
                  the Depositary in accordance with the Applicable Procedures
                  directing the Depositary to cause to be issued a Definitive
                  Note in an amount equal to the beneficial interest to be
                  transferred or exchanged and (2) instructions given by the
                  Depositary to the Registrar containing information regarding
                  the Person in whose name such Definitive Note shall be
                  registered to effect the transfer or exchange referred to in
                  (1) above. Upon satisfaction of all of the requirements for
                  transfer or exchange of beneficial interests in Global Notes
                  contained in this Indenture and the Notes or otherwise
                  applicable under the Securities Act, the Trustee shall adjust
                  the principal amount of the relevant Global Note(s) pursuant
                  to Section 2.06(g) hereof.

            (iii) Restricted Global Note to Regulation S Global Note. If the
                  owner of a beneficial interest in the Restricted Global Note
                  wishes at any time to transfer such interest to a Person who
                  wishes to acquire the same in the form of a beneficial
                  interest in the Regulation S Global Note, such transfer may be
                  effected only in accordance with the provisions of this clause
                  (iii) and clause (v) below and subject to the Applicable
                  Procedures. Upon receipt by the Trustee, as Registrar, of (A)
                  an order given by the Depositary or its authorized
                  representative directing that a beneficial interest in the
                  Regulation S Global Note in a specified principal amount be
                  credited to a specified Participant's account and that a
                  beneficial interest in the Restricted Global Note in an equal
                  principal amount be debited from another specified
                  Participant's account and (B) a Regulation S Certificate,
                  satisfactory to the Trustee and duly executed by the owner of
                  such beneficial interest in the Restricted Global Note or his
                  attorney duly authorized in writing, then the Trustee, as
                  Registrar but subject to clause (v) below, shall reduce the
                  principal amount of the Restricted Global Note and increase
                  the principal amount of the Regulation S Global Note by such
                  specified principal amount.

            (iv)  Regulation S Global Note to Restricted Global Note. If the
                  owner of a beneficial interest in the Regulation S Global Note
                  wishes at any time to transfer such interest to a Person who
                  wishes to acquire the same in the form of a beneficial
                  interest in the Restricted Global Note, such transfer may be
                  effected only in accordance with this clause (iv) and subject
                  to the Applicable Procedures. Upon receipt by the Trustee, as
                  Registrar, of (A) an order given by the Depositary or its
                  authorized representative directing that a beneficial interest
                  in the Restricted Global Note in a specified

                                      35
<PAGE>

                  principal amount be credited to a specified Participant's
                  account and that a beneficial interest in the Regulation S
                  Global Note in an equal principal amount be debited from
                  another specified Participant's account and (B) if such
                  transfer is to occur during the Restricted Period, a
                  Restricted Notes Certificate, satisfactory to the Trustee and
                  duly executed by the owner of such beneficial interest in the
                  Regulation S Global Note or his attorney duly authorized in
                  writing, then the Trustee, as Registrar, shall reduce the
                  principal amount of the Regulation S Global Note and increase
                  the principal amount of the Restricted Global Note by such
                  specified principal amount.

            (v)   Regulation S Global Note to be Held Through Euroclear or
                  Clearsteam during Restricted Period. The Company shall use its
                  best efforts to cause the Depositary to ensure that, until the
                  expiration of the Restricted Period, beneficial interests in
                  the Regulation S Global Note may be held only in or through
                  accounts maintained at the Depositary by Euroclear or
                  Clearsteam (or by Participants acting for the account
                  thereof), and no person shall be entitled to effect any
                  transfer or exchange that would result in any such interest
                  being held otherwise than in or through such an account;
                  provided that this clause (v) shall not prohibit any transfer
                  or exchange of such an interest in accordance with clause (iv)
                  above.

     (c) Transfer or Exchange of Beneficial Interests for Definitive Notes. If
any Holder of a beneficial interest in a Global Note proposes to exchange such
beneficial interest for a Definitive Note or to transfer such beneficial
interest to a Person who takes delivery thereof in the form of a Definitive
Note, then, upon satisfaction of the conditions set forth in Sections 2.06(a)
and 2.06(b)(ii) hereof, the Trustee shall cause the aggregate principal amount
of the applicable Global Note to be reduced accordingly pursuant to Section
2.06(g) hereof, and the Company shall execute and the Trustee shall authenticate
and deliver to the Person designated in the instructions a Definitive Note in
the appropriate principal amount. Any Definitive Note issued in exchange for a
beneficial interest pursuant to this Section 2.06(c) shall bear the legend
restricting transfers that is borne by such Global Note and shall be registered
in such name or names and in such authorized denomination or denominations as
the holder of such beneficial interest shall instruct the Registrar through
instructions from the Depositary and the Participant or Indirect Participant.

     (d) [Intentionally omitted]

     (e) Transfer and Exchange of Definitive Notes for Definitive Notes. Upon
request by a Holder of Definitive Notes and such requesting Holder's presenting
or surrendering to the Registrar the Definitive Notes duly endorsed or
accompanied by a written instruction of transfer in form satisfactory to the
Registrar duly executed by such Holder or by its attorney, duly authorized in
writing, the Registrar shall register the transfer or exchange of Definitive
Notes; provided that, if the Note to be transferred in whole or in part is a
Restricted Note, or is a Regulation S Note and the transfer is to occur during
the Restricted Period, then the Trustee shall

                                      36
<PAGE>

have received (A) a Restricted Notes Certificate, satisfactory to the Trustee
and duly executed by the transferor Holder or his attorney duly authorized in
writing, in which case the transferee Holder shall take delivery in the form of
a Restricted Note, or (B) a Regulation S Certificate, satisfactory to the
Trustee and duly executed by the transferor Holder or his attorney duly
authorized in writing, in which case the transferee Holder shall take delivery
in the form of a Regulation S Note (subject in every case to Section 2.06(f)).

     (f) Legends.

         (i)   Global Notes Legends. Each Global Note shall bear a legend in
               substantially the following form:

     "THIS GLOBAL NOTE IS HELD BY THE DEPOSITARY (AS DEFINED IN THE INDENTURE
GOVERNING THIS NOTE) OR ITS NOMINEE IN CUSTODY FOR THE BENEFIT OF THE BENEFICIAL
OWNERS HEREOF, AND IS NOT TRANSFERABLE TO ANY PERSON UNDER ANY CIRCUMSTANCES
EXCEPT THAT (I) THE TRUSTEE MAY MAKE SUCH NOTATIONS HEREON AS MAY BE REQUIRED
PURSUANT TO SECTION 2.06 OF THE INDENTURE, (II) THIS GLOBAL NOTE MAY BE
EXCHANGED IN WHOLE BUT NOT IN PART PURSUANT TO SECTION 2.06(a) OF THE INDENTURE,
(III) THIS GLOBAL NOTE MAY BE DELIVERED TO THE TRUSTEE FOR CANCELLATION PURSUANT
TO SECTION 2.11 OF THE INDENTURE AND (IV) THIS GLOBAL NOTE MAY BE TRANSFERRED TO
A SUCCESSOR DEPOSITARY WITH THE PRIOR WRITTEN CONSENT OF AMERICAN TOWER
CORPORATION."

          (ii) Securities Act Legends. Rule 144A Notes and their Successor Notes
               shall bear a Restricted Notes Legend, and the Regulation S Notes
               and their Successor Notes shall bear a Regulation S Legend,
               subject to the following:

               (1)  subject to the following sub-clauses of this clause (ii), a
                    Note or any portion thereof which is exchanged, upon
                    transfer or otherwise, for a Global Note or any portion
                    thereof shall bear the Securities Act Legend borne by such
                    Global Note while represented thereby;

               (2)  subject to the following sub-clauses of this clause (ii), a
                    new Note which is not a Global Note and is issued in
                    exchange for another Note (including a Global Note) or any
                    portion thereof, upon transfer or otherwise, shall bear the
                    Securities Act Legend borne by such other Note, provided
                    that, if such new Note is required pursuant to Section
                    2.06(a) to be issued in the form of a Restricted Note, it
                    shall bear a Restricted Note Legend and, if such new Note is
                    so required to be issued in the form of a Regulation S Note,
                    it shall bear a Regulation S Legend;

                                      37
<PAGE>

               (3)  Registered Notes shall not bear a Securities Act Legend;

               (4)  at any time after the Notes may be freely transferred
                    without registration under the Securities Act or without
                    being subject to transfer restrictions pursuant to the
                    Securities Act, a new Note which does not bear a Securities
                    Act Legend may be issued in exchange for or in lieu of a
                    Note (other than a Global Note) or any portion thereof which
                    bears such a legend if the Trustee has received an
                    Unrestricted Notes Certificate, satisfactory to the Trustee
                    and duly executed by the Holder of such legended Note or his
                    attorney duly authorized in writing, and after such date and
                    receipt of such certificate, the Trustee shall authenticate
                    and deliver such a new Note in exchange for or in lieu of
                    such other Note as provided in this Article 2;

               (5)  a new Note which does not bear a Securities Act Legend may
                    be issued in exchange for or in lieu of a Note (other than a
                    Global Note) or any portion thereof which bears such a
                    legend if, in the Company's judgment, placing such a legend
                    upon such new Note is not necessary to ensure compliance
                    with the registration requirements of the Securities Act,
                    and the Trustee, at the written direction of the Company,
                    shall authenticate and deliver such new Note as provided in
                    this Article 2; and

               (6)  notwithstanding the foregoing provisions of this clause (ii)
                    of Section 2.06(f), a Successor Note of a Note that does not
                    bear a particular form of Securities Act Legend shall not
                    bear such form of legend unless the Company has reasonable
                    cause to believe that such Successor Note is a "restricted
                    security" within the meaning of Rule 144, in which case the
                    Trustee, at the direction of the Company, shall authenticate
                    and deliver a new Note bearing a Restricted Notes Legend in
                    exchange for such Successor Note as provided in this Article
                    2.

      (g) Cancellation and/or Adjustment of Global Notes. At such time as all
beneficial interests in a particular Global Note have been exchanged for
Definitive Notes or a particular Global Note has been redeemed, repurchased or
canceled in whole and not in part, each such Global Note shall be returned to or
retained and canceled by the Trustee in accordance with Section 2.11 hereof. At
any time prior to such cancellation, if any beneficial interest in a Global Note
is exchanged for or transferred to a Person who will take delivery thereof in
the form of a beneficial interest in another Global Note or for Definitive
Notes, the principal amount of Notes represented by such Global Note shall be
reduced accordingly and an endorsement shall be made on such Global Note by the
Trustee or by the Depositary at the direction of the Trustee to reflect such
reduction; and if the beneficial interest is being exchanged for or transferred
to a Person who will take delivery thereof in the form of a beneficial interest
in another Global Note, such

                                      38
<PAGE>

other Global Note shall be increased accordingly and an endorsement shall be
made on such Global Note by the Trustee or by the Depositary at the direction of
the Trustee to reflect such increase.

       (h)    General Provisions Relating to Transfers and Exchanges.

              (i)    To permit registrations of transfers and exchanges, the
                     Company shall execute and the Trustee shall authenticate
                     Global Notes and Definitive Notes upon the Company's order
                     or at the Registrar's request.

              (ii)   No service charge shall be made to a holder of a beneficial
                     interest in a Global Note or to a Holder of a Definitive
                     Note for any registration of transfer or exchange, but the
                     Company may require payment of a sum sufficient to cover
                     any transfer tax or similar governmental charge payable in
                     connection therewith (other than any such transfer taxes or
                     similar governmental charge payable upon exchange or
                     transfer pursuant to Sections 2.10, 3.06, 3.09, 4.10, 4.14
                     and 9.05 hereof).

              (iii)  The Registrar shall not be required to register the
                     transfer of or exchange any Note selected for redemption in
                     whole or in part, except the unredeemed portion of any Note
                     being redeemed in part.

              (iv)   All Global Notes and Definitive Notes issued upon any
                     registration of transfer or exchange of Global Notes or
                     Definitive Notes shall be the valid obligations of the
                     Company, evidencing the same debt, and entitled to the same
                     benefits under this Indenture, as the Global Notes or
                     Definitive Notes surrendered upon such registration of
                     transfer or exchange.

              (v)    The Company shall not be required (A) to issue, to register
                     the transfer of or to exchange any Notes during a period
                     beginning at the opening of business 15 days before the day
                     of any selection of Notes for redemption under Section 3.02
                     hereof and ending at the close of business on the day of
                     selection, (B) to register the transfer of or to exchange
                     any Note so selected for redemption in whole or in part,
                     except the unredeemed portion of any Note being redeemed in
                     part or (C) to register the transfer of or to exchange a
                     Note between a record date and the next succeeding Interest
                     Payment Date.

              (vi)   Prior to due presentment for the registration of a transfer
                     of any Note, the Trustee, any Agent and the Company may
                     deem and treat the Person in whose name any Note is
                     registered as the absolute owner of such Note for the
                     purpose of receiving payment of principal of and premium,
                     if any, and interest on such Notes and for all other
                     purposes, and none of the Trustee, any Agent or the Company
                     shall be affected by notice to the contrary.

                                      39
<PAGE>

              (vii)  The Trustee shall authenticate Global Notes and Definitive
                     Notes in accordance with the provisions of Section 2.02
                     hereof.

              (viii) All certifications, certificates and Opinions of Counsel
                     required to be submitted to the Registrar pursuant to this
                     Section 2.06 to effect a registration of transfer or
                     exchange may be submitted by facsimile.

       Section 2.07. Replacement Notes.

       If any mutilated Note is surrendered to the Trustee or the Company and
the Trustee receives evidence to its satisfaction of the destruction, loss or
theft of any Note, the Company shall issue and the Trustee, upon receipt of an
Authentication Order, shall authenticate a replacement Note if the Trustee's
requirements are met. If required by the Trustee or the Company, an indemnity
bond must be supplied by the Holder that is sufficient in the judgment of the
Trustee and the Company to protect the Company, the Trustee, any Agent and any
authenticating agent from any loss that any of them may suffer if a Note is
replaced. The Company may charge for its expenses in replacing a Note.

       Every replacement Note is an additional obligation of the Company and
shall be entitled to all of the benefits of this Indenture equally and
proportionately with all other Notes duly issued hereunder.

       Section 2.08. Outstanding Notes.

       The Notes outstanding at any time are all the Notes authenticated by the
Trustee except for those canceled by it, those delivered to it for cancellation,
those reductions in the interest in a Global Note effected by the Trustee in
accordance with the provisions hereof, and those described in this Section as
not outstanding. Except as set forth in Section 2.09 hereof, a Note does not
cease to be outstanding because the Company or an Affiliate of the Company holds
the Note; however, Notes held by the Company or a Subsidiary of the Company
shall not be deemed to be outstanding for purposes of Section 3.07(b) hereof.

       If a Note is replaced pursuant to Section 2.07 hereof, it ceases to be
outstanding unless the Trustee receives proof satisfactory to it that the
replaced Note is held by a bona fide purchaser.

       If the principal amount of any Note is considered paid under Section 4.01
hereof, it ceases to be outstanding and interest on it ceases to accrue.

       If the Paying Agent (other than the Company, a Subsidiary or an Affiliate
of any thereof) holds, on a redemption date or maturity date, money sufficient
to pay Notes payable on that date, then on and after that date such Notes shall
be deemed to be no longer outstanding and shall cease to accrue interest.

                                      40
<PAGE>

       Section 2.09. Treasury Notes.

       In determining whether the Holders of the required principal amount of
Notes have concurred in any direction, waiver or consent, Notes owned by the
Company, or by any Person directly or indirectly controlling or controlled by or
under direct or indirect common control with the Company, shall be considered as
though not outstanding, except that for the purposes of determining whether the
Trustee shall be protected in relying on any such direction, waiver or consent,
only Notes that the Trustee knows are so owned shall be so disregarded.

       Section 2.10. Temporary Notes.

       Until certificates representing Notes are ready for delivery, the Company
may prepare and the Trustee, upon receipt of an Authentication Order, shall
authenticate temporary Notes. Temporary Notes shall be substantially in the form
of certificated Notes but may have variations that the Company considers
appropriate for temporary Notes and as shall be reasonably acceptable to the
Trustee. Without unreasonable delay, the Company shall prepare and the Trustee
shall authenticate definitive Notes in exchange for temporary Notes.

       Holders of temporary Notes shall be entitled to all of the benefits of
this Indenture.

       Section 2.11. Cancellation.

       The Company at any time may deliver Notes to the Trustee for
cancellation. The Registrar and Paying Agent shall forward to the Trustee any
Notes surrendered to them for registration of transfer, exchange or payment. The
Trustee and no one else shall cancel all Notes surrendered for registration of
transfer, exchange, payment, replacement or cancellation and shall dispose of
such cancelled Notes in its customary manner in accordance with prudent business
practices. The Company may not issue new Notes to replace Notes that it has paid
or that have been delivered to the Trustee for cancellation except as expressly
permitted pursuant to this Indenture.

       Section 2.12. Defaulted Interest.

       If the Company defaults in a payment of interest on the Notes, it shall
pay the defaulted interest in any lawful manner, plus, to the extent lawful,
interest payable on the defaulted interest, to the Persons who are Holders on a
subsequent special record date, in each case at the rate provided in the Notes
and in Section 4.01 hereof. The Company shall notify the Trustee in writing of
the amount of defaulted interest proposed to be paid on each Note and the date
of the proposed payment. The Company shall fix or cause to be fixed each such
special record date and payment date, provided that no such special record date
shall be less than 10 days prior to the related payment date for such defaulted
interest. At least 15 days before the special record date, the Company (or, upon
the written request of the Company, the Trustee in the name and at the expense
of the Company) shall mail or cause to be mailed to Holders a notice that states
the special record date, the related payment date and the amount of such
interest to be paid.

                                      41
<PAGE>

       Section 2.13. CUSIP Numbers.

       The Trustee shall use "CUSIP" numbers in notices of redemption as a
convenience to Holders if the Company uses "CUSIP" numbers in issuing the Notes;
provided that any such notice may state that no representation is made as to the
correctness of such numbers either as printed on the Notes or as contained in
any notice of a redemption and that reliance may be placed only on the other
identification numbers printed on the Notes, and any such redemption shall not
be affected by any defect in or omission of such numbers. The Company will
promptly notify the Trustee of any change in the "CUSIP" numbers.

                                   ARTICLE 3

                           REDEMPTION AND PREPAYMENT

       Section 3.01. Notices to Trustee.

       If the Company elects to redeem Notes pursuant to the optional redemption
provisions of Section 3.07 hereof, it shall furnish to the Trustee, at least 30
days but not more than 60 days before a redemption date, an Officers'
Certificate setting forth (1) the clause of this Indenture pursuant to which the
redemption shall occur, (2) the redemption date, (3) the principal amount of
Notes to be redeemed and (4) the redemption price (expressed as a percentage of
the principal amount).

       Section 3.02. Selection of Notes to Be Redeemed.

       If less than all of the Notes are to be redeemed or purchased in an offer
to purchase at any time, the Trustee shall select the Notes to be redeemed as
follows:

              (1)    if the Notes are listed on any national securities
                     exchange, in compliance with the requirements of the
                     principal national securities exchange, if any, on which
                     the Notes are listed; or

              (2)    if the Notes are not listed on any national securities
                     exchange, on a pro rata basis.

       No Notes of $1,000 of principal amount or less will be redeemed in part.
Except as provided in the preceding sentence, provisions of this Indenture that
apply to Notes called for redemption also apply to portions of Notes called for
redemption.

       Notes called for redemption become due on the date fixed for redemption.

       Section 3.03. Notice of Redemption.

       Subject to the provisions of Section 3.09 hereof, at least 30 days but
not more than 60 days before a redemption date, the Company shall mail or cause
to be mailed, by first class mail,

                                      42
<PAGE>

a notice of redemption to each Holder whose Notes are to be redeemed at its
registered address. Notices of redemption may not be conditional.

       The notice shall identify the Notes to be redeemed and shall state:

              (1)    the redemption date;

              (2)    the redemption price;

              (3)    if any Note is being redeemed in part, the portion of the
                     principal amount of such Note to be redeemed and that,
                     after the redemption date upon surrender of such Note, a
                     new Note or Notes in principal amount equal to the
                     unredeemed portion shall be issued upon cancellation of the
                     original Note;

              (4)    the name and address of the Paying Agent;

              (5)    that Notes called for redemption must be surrendered to the
                     Paying Agent to collect the redemption price;

              (6)    that, unless the Company defaults in making such redemption
                     payment, interest on Notes called for redemption ceases to
                     accrue on and after the redemption date;

              (7)    the paragraph of the Notes and/or Section of this Indenture
                     pursuant to which the Notes called for redemption are being
                     redeemed; and

              (8)    that no representation is made as to the correctness or
                     accuracy of the CUSIP number, if any, listed in such notice
                     or printed on the Notes.

       At the Company's request, the Trustee shall give the notice of redemption
in the Company's name and at its expense; provided, however, that the Company
shall have delivered to the Trustee, at least 45 days prior to the redemption
date, an Officers' Certificate requesting that the Trustee give such notice and
setting forth the information to be stated in such notice as provided in the
preceding paragraph.

       Section 3.04. Effect of Notice of Redemption.

       Once notice of redemption is mailed in accordance with Section 3.03
hereof, Notes called for redemption become irrevocably due and payable on the
redemption date at the redemption price.

                                      43
<PAGE>

       Section 3.05. Deposit of Redemption Price.

       One Business Day prior to the redemption date, the Company shall deposit
with the Trustee or with the Paying Agent money sufficient to pay the redemption
price of and accrued interest on all Notes to be redeemed on that date. The
Trustee or the Paying Agent shall promptly return to the Company any money
deposited with the Trustee or the Paying Agent by the Company in excess of the
amounts necessary to pay the redemption price of, and accrued interest on, all
Notes to be redeemed.

       If the Company complies with the provisions of the preceding paragraph,
on and after the redemption date, interest shall cease to accrue on the Notes or
the portions of the Notes called for redemption. If a Note is redeemed on or
after an interest record date but on or prior to the related interest payment
date, then any accrued and unpaid interest shall be paid to the Person in whose
name such Note was registered at the close of business on such record date. If
any Note called for redemption shall not be so paid upon surrender for
redemption because of the failure of the Company to comply with the preceding
paragraph, interest shall be paid on the unpaid principal, from the redemption
date until such principal is paid, and, to the extent lawful, on any interest
not paid on such unpaid principal, in each case at the rate provided in the
Notes and in Section 4.01 hereof.

       Section 3.06. Notes Redeemed in Part.

       Upon surrender of a Note that is redeemed in part, the Company shall
issue and, upon the Company's written request, the Trustee shall authenticate
for the Holder at the expense of the Company a new Note equal in principal
amount to the unredeemed portion of the Note surrendered. If a Global Note is so
surrendered, such new Note shall also be a Global Note.

       Section 3.07. Optional Redemption.

       (a) Except as provided in clauses (b) and (c) of this Section 3.07, the
Notes will not be redeemable at the Company's option prior to February 1, 2005.
On or after February 1, 2005, the Company may redeem all or a part of the Notes
upon not less than 30 nor more than 60 days' notice, at the redemption prices
(expressed as percentages of principal amount) set forth below plus accrued and
unpaid interest, if any, on the Notes redeemed to the applicable redemption date
(subject to the right of Holders of record on the relevant record date to
receive interest due on the relevant interest payment date), if redeemed during
the twelve-month period beginning on February 1 of the years indicated below:

       Year                                                  Percentage
       ----                                                  ----------
       2005................................................  104.688 %
       2006................................................  103.125
       2007................................................  101.562
       2008 and thereafter.................................  100.000

                                      44
<PAGE>

       (b) Notwithstanding the provisions of clause (a) of this Section 3.07, at
any time until February 1, 2004, the Company may on any one or more occasions
redeem Notes (including Exchange Notes) representing up to 35% of the aggregate
principal amount of the Notes originally issued under the Indenture (excluding
any Exchange Notes) at a redemption price equal to 109.375% of the aggregate
principal amount of the Notes to be redeemed on the redemption date with the net
cash proceeds of one or more Public Equity Offerings and/or Strategic Equity
Investments provided that:

              (1)    Notes (including Exchange Notes) representing at least 65%
                     of the aggregate principal amount of the Notes originally
                     issued under the Indenture (excluding any Exchange Notes)
                     remain outstanding immediately after the occurrence of such
                     redemption (excluding Notes held by the Company or any of
                     its Subsidiaries); and

              (2)    the redemption occurs within 60 days of the date of the
                     closing of such Public Equity Offering or Strategic Equity
                     Investment.

       (c) Notwithstanding the provisions of clause (a) of this Section 3.07, at
any time prior to February 1, 2005, the Company may redeem all or a part of the
Notes upon not less than 30 nor more than 60 days' notice at a redemption price
equal to 100% of the principal amount thereof plus the Applicable Premium as of,
and accrued and unpaid interest, if any, to, the date of redemption.

       (d) Any redemption pursuant to this Section 3.07 shall be made pursuant
to the provisions of Section 3.01 through 3.06 hereof.

       Section 3.08. Mandatory Redemption.

       The Company shall not be required to make mandatory redemption or sinking
fund payments with respect to the Notes.

       Section 3.09. Offer to Purchase by Application of Excess Proceeds.

       In the event that, pursuant to Section 4.10 hereof, the Company shall be
required to commence an offer to all Holders to purchase Notes (an "Asset Sale
Offer"), it shall follow the procedures specified below.

       The Asset Sale Offer shall remain open for a period of 20 Business Days
following its commencement and no longer, except to the extent that a longer
period is required by applicable law (the "Offer Period"). No later than five
Business Days after the termination of the Offer Period (the "Purchase Date"),
the Company shall purchase the aggregate principal amount (or accreted value, as
applicable) of Notes and other unsubordinated Indebtedness of the Company
required to be purchased pursuant to Section 4.10 hereof (on a pro rata basis if
Notes and other unsubordinated Indebtedness of the Company tendered are in
excess of the Excess Proceeds) (which maximum amount shall be the "Offer
Amount") or, if less than the Offer Amount has been tendered, all Notes and
other unsubordinated Indebtedness tendered in response to the Asset

                                      45
<PAGE>

Sale Offer. Payment for any Notes so purchased shall be made in the same manner
as interest payments are made.

       If the Purchase Date is on or after an interest record date and on or
before the related interest payment date, any accrued and unpaid interest shall
be paid to the Person in whose name a Note is registered at the close of
business on such record date, and no additional interest shall be payable to
Holders who tender Notes pursuant to the Asset Sale Offer.

       Upon the commencement of an Asset Sale Offer, the Company shall send, by
first class mail, a notice to the Trustee and each of the Holders, with a copy
to the Trustee. The notice shall contain all instructions and materials
necessary to enable such Holders to tender Notes pursuant to the Asset Sale
Offer. The Asset Sale Offer shall be made to all Holders. The notice, which
shall govern the terms of the Asset Sale Offer, shall state:

              (i)    that the Asset Sale Offer is being made pursuant to this
                     Section 3.09 and Section 4.10 hereof and the length of time
                     the Asset Sale Offer shall remain open;

              (ii)   the Offer Amount, the purchase price and the Purchase Date;

              (iii)  that any Note not tendered or accepted for payment shall
                     continue to accrue interest;

              (iv)   that, unless the Company defaults in making such payment,
                     any Note accepted for payment pursuant to the Asset Sale
                     Offer shall cease to accrue interest after the Purchase
                     Date;

              (v)    that Holders electing to have a Note purchased pursuant to
                     an Asset Sale Offer may elect to have Notes purchased in
                     integral multiples of $1,000 only;

              (vi)   that Holders electing to have a Note purchased pursuant to
                     any Asset Sale Offer shall be required to surrender the
                     Note, with the form entitled "Option of Holder to Elect
                     Purchase" on the reverse of the Note completed, or transfer
                     by book-entry transfer, to the Company, a Depositary, if
                     appointed by the Company, or a Paying Agent at the address
                     specified in the notice at least three days before the
                     Purchase Date;

              (vii)  that Holders shall be entitled to withdraw their election
                     if the Company, the Depositary or the Paying Agent, as the
                     case may be, receives, not later than the expiration of the
                     Offer Period, a telegram, telex, facsimile transmission or
                     letter setting forth the name of the Holder, the principal
                     amount of the Note the Holder delivered for purchase and a
                     statement that such Holder is withdrawing his election to
                     have such Note purchased;

                                      46
<PAGE>

              (viii) that, if the aggregate principal amount (or accreted value,
                     as applicable) of Notes and other unsubordinated
                     Indebtedness of the Company surrendered by Holders exceeds
                     the Offer Amount, the Company shall select the Notes to be
                     purchased on a pro rata basis (with such adjustments as may
                     be deemed appropriate by the Company so that only Notes in
                     denominations of $1,000, or integral multiples thereof,
                     shall be purchased); and

              (ix)   that Holders whose Notes were purchased only in part shall
                     be issued new Notes equal in principal amount to the
                     unpurchased portion of the Notes surrendered (or
                     transferred by book-entry transfer).

       On or before the Purchase Date, the Company shall, to the extent lawful,
accept for payment, on a pro rata basis to the extent necessary, the Offer
Amount of Notes or portions thereof tendered pursuant to the Asset Sale Offer,
or if less than the Offer Amount has been tendered, all Notes and other
unsubordinated Indebtedness tendered, and shall deliver to the Trustee an
Officers' Certificate stating that the Notes or portions thereof were accepted
for payment by the Company in accordance with the terms of this Section 3.09.
The Company, the Depositary or the Paying Agent, as the case may be, shall
promptly (but in any case not later than five days after the Purchase Date) mail
or deliver to each tendering Holder an amount equal to the purchase price of the
Notes tendered by such Holder and accepted by the Company for purchase, and the
Company shall promptly issue a new Note, and the Trustee, upon written request
from the Company shall authenticate and mail or deliver such new Note to such
Holder, in a principal amount equal to any unpurchased portion of the Note
surrendered. Any Note not so accepted shall be promptly mailed or delivered by
the Company to the Holder thereof. The Company shall publicly announce the
results of the Asset Sale Offer on the Purchase Date.

       Other than as specifically provided in this Section 3.09, any purchase
pursuant to this Section 3.09 shall be made pursuant to the provisions of
Sections 3.01 through 3.06 hereof.

       The provisions under this Indenture relating to the Company's obligation
to make an Asset Sale Offer may be waived or modified with the written consent
of the Holders of a at least a majority in principal amount of the Notes then
outstanding.

                                   ARTICLE 4

                                   COVENANTS

       Section 4.01. Payment of Notes.

       The Company shall pay or cause to be paid the principal of, premium, if
any, and interest on the Notes on the dates and in the manner provided in the
Notes. Principal, premium, if any, and interest shall be considered paid on the
date due if the Paying Agent, if other than the Company or a Subsidiary thereof,
holds as of 10:00 a.m., Eastern Time, on the due date money deposited by the
Company in immediately available funds and designated for and sufficient to pay
all principal, premium, if any, and interest then due.

                                      47
<PAGE>

       The Company shall pay interest (including post-petition interest in any
proceeding under any Bankruptcy Law) on overdue principal at the rate equal to
1% per annum in excess of the then applicable interest rate on the Notes to the
extent lawful; it shall pay interest (including post-petition interest in any
proceeding under any Bankruptcy Law) on overdue installments of interest
(without regard to any applicable grace period) at the same rate to the extent
lawful.

       Section 4.02. Maintenance of Office or Agency.

       The Company shall maintain in the Borough of Manhattan, The City of New
York, an office or agency (which may be an office of the Trustee or an affiliate
of the Trustee, Registrar or co-registrar) where Notes may be surrendered for
registration of transfer or for exchange and where notices and demands to or
upon the Company in respect of the Notes and this Indenture may be served. The
Company shall give prompt written notice to the Trustee of the location, and any
change in the location, of such office or agency. If at any time the Company
shall fail to maintain any such required office or agency or shall fail to
furnish the Trustee with the address thereof, such presentations, surrenders,
notices and demands may be made or served at the Corporate Trust Office of the
Trustee.

       The Company may also from time to time designate one or more other
offices or agencies where the Notes may be presented or surrendered for any or
all such purposes and may from time to time rescind such designations; provided,
however, that no such designation or rescission shall in any manner relieve the
Company of its obligation to maintain an office or agency in the Borough of
Manhattan, The City of New York, for such purposes. The Company shall give
prompt written notice to the Trustee of any such designation or rescission and
of any change in the location of any such other office or agency.

       The Company hereby designates the Corporate Trust Office of the Trustee
as one such office or agency of the Company in accordance with Section 2.03
hereof.

       Section 4.03. Reports.

       Whether or not required by the SEC, so long as any Notes are outstanding,
the Company shall furnish to the Holders of Notes:

              (1)    all quarterly and annual financial information that would
                     be required to be contained in a filing with the SEC on
                     Forms 10-Q and 10-K if the Company were required to file
                     such Forms, including a "Management's Discussion and
                     Analysis of Financial Condition and Results of Operations"
                     that describes the financial condition and results of
                     operations of the Company and its consolidated Subsidiaries
                     (showing in reasonable detail, in the footnotes to the
                     financial statements and in the "Management's Discussion
                     and Analysis of Financial Condition and Results of
                     Operations" (in each case to the extent not prohibited by
                     the SEC's rules and regulations):

                                      48
<PAGE>

                     (a)    the financial condition and results of operations of
                            the Company and its Restricted Subsidiaries separate
                            from the financial condition and results of
                            operations of the Unrestricted Subsidiaries of the
                            Company; and

                     (b)    the Tower Cash Flow for the most recently completed
                            fiscal quarter and the Adjusted Consolidated Cash
                            Flow and Non-Tower Cash Flow for the most recently
                            completed four-quarter period) and, with respect to
                            the annual information only, a report thereon by the
                            Company's certified independent accountants; and

              (2)    all current reports that would be required to be filed with
                     the SEC on Form 8-K if the Company were required to file
                     such reports,

       in each case within the time periods specified in the SEC's rules and
regulations.

       In addition, whether or not required by the rules and regulations of the
SEC, the Company shall file a copy of all such information and reports with the
SEC for public availability within the time periods specified in the SEC's rules
and regulations (unless the SEC will not accept such a filing) and make such
information available to securities analysts and prospective investors upon
request. The Company shall at all times comply with TIA (S). 314(a).

       Section 4.04. Compliance Certificate.

              (1)    The Company shall deliver to the Trustee, within 90 days
                     after the end of each fiscal year, an Officers' Certificate
                     stating that a review of the activities of the Company and
                     its Subsidiaries during the preceding fiscal year has been
                     made under the supervision of the signing Officers with a
                     view to determining whether the Company has kept, observed,
                     performed and fulfilled its obligations under this
                     Indenture, and further stating, as to each such Officer
                     signing such certificate, that to the best of his or her
                     knowledge the Company has kept, observed, performed and
                     fulfilled each and every covenant contained in this
                     Indenture and is not in default in the performance or
                     observance of any of the terms, provisions and conditions
                     of this Indenture (or, if a Default or Event of Default
                     shall have occurred, describing all such Defaults or Events
                     of Default of which he or she may have knowledge and what
                     action the Company is taking or proposes to take with
                     respect thereto).

              (2)    The Company shall, so long as any of the Notes are
                     outstanding, deliver to the Trustee, forthwith upon any
                     Officer becoming aware of any Default or Event of Default,
                     an Officers' Certificate specifying such Default or Event
                     of Default and what action the Company is taking or
                     proposes to take with respect thereto.

                                      49
<PAGE>

       Section 4.05. Taxes.

       The Company shall pay, and shall cause each of its Subsidiaries to pay,
prior to delinquency, all material taxes, assessments, and governmental levies
except such as are contested in good faith and by appropriate proceedings or
where the failure to effect such payment is not adverse in any material respect
to the Holders of the Notes.

       Section 4.06. Stay, Extension and Usury Laws.

       The Company covenants (to the extent that it may lawfully do so) that it
shall not at any time insist upon, plead, or in any manner whatsoever claim or
take the benefit or advantage of, any stay, extension or usury law wherever
enacted, now or at any time hereafter in force, that may affect the covenants or
the performance of this Indenture; and the Company (to the extent that it may
lawfully do so) hereby expressly waives all benefit or advantage of any such
law, and covenants that it shall not, by resort to any such law, hinder, delay
or impede the execution of any power herein granted to the Trustee, but shall
suffer and permit the execution of every such power as though no such law has
been enacted.

       Section 4.07. Restricted Payments.

       The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, directly or indirectly:

              (1)    declare or pay any dividend or make any other payment or
                     distribution on account of the Company's or any of its
                     Restricted Subsidiaries' Equity Interests (including,
                     without limitation, any payment in connection with any
                     merger or consolidation involving the Company or any of its
                     Restricted Subsidiaries) or to the direct or indirect
                     holders of the Company's or any of its Restricted
                     Subsidiaries' Equity Interests in their capacity as such
                     (other than dividends or distributions payable (i) in
                     Equity Interests (other than Disqualified Stock) of the
                     Company or (ii) to the Company or a Restricted Subsidiary
                     of the Company);

              (2)    purchase, redeem or otherwise acquire or retire for value
                     (including without limitation, in connection with any
                     merger or consolidation involving the Company) any Equity
                     Interests of the Company or of any Person of which the
                     Company is a Subsidiary (other than any such Equity
                     Interests owned by the Company or any of its Restricted
                     Subsidiaries);

              (3)    make any payment on or with respect to, or purchase,
                     redeem, defease or otherwise acquire or retire for value
                     any Indebtedness that is subordinated to the Notes, except
                     a payment of interest or principal at Stated Maturity
                     (other than payments to the Company or payments by a
                     Restricted Subsidiary of the Company to the Company or
                     another Restricted Subsidiary of the Company); or

                                      50
<PAGE>

              (4)    make any Restricted Investment, (all such payments and
                     other actions restricted by these clauses (1) through (4),
                     being collectively referred to as "Restricted Payments"),

       unless, at the time of and after giving effect to such Restricted
Payment:

              (1)    no Default has occurred and is continuing or would occur as
                     a consequence of the Restricted Payment; and

              (2)    the Company would have been permitted to incur at least
                     $1.00 of additional Indebtedness pursuant to the Debt to
                     Adjusted Consolidated Cash Flow Ratio test set forth in the
                     first paragraph of Section 4.09 hereof; provided that the
                     Company and its Restricted Subsidiaries shall not be
                     required to comply with this clause (2) in order to make
                     any Restricted Investment or to declare or pay any Excepted
                     Verestar Dividend; and

              (3)    such Restricted Payment, together with the aggregate amount
                     of all other Restricted Payments made by the Company and
                     its Restricted Subsidiaries after the Issue Date (excluding
                     Restricted Payments permitted by clauses (2), (3) and (4)
                     of the paragraph of exceptions below), is less than the
                     sum, without duplication, of:

                     (a)    100% of the Consolidated Cash Flow of the Company
                            for the period (taken as one accounting period) from
                            the beginning of the fiscal quarter during which the
                            Issue Date falls to the end of the Company's most
                            recently ended fiscal quarter for which internal
                            financial statements are available at the time of
                            such Restricted Payment (or, if the Consolidated
                            Cash Flow for such period is a deficit, less 100% of
                            the deficit), less 1.40 times the Consolidated
                            Interest Expense of the Company since the beginning
                            of the fiscal quarter during which the Issue Date
                            falls to the end of the Company's most recently
                            ended fiscal quarter for which internal financial
                            statements are available at the time of such
                            Restricted Payment; plus

                     (b)    (i) 100% of the aggregate net cash proceeds plus
                            (ii) 70% of the aggregate value, as reflected on the
                            Company's balance sheet in accordance with GAAP
                            using purchase accounting, of any Qualified
                            Proceeds, in each case as of the date the Company's
                            Equity Interests were issued, sold or exchanged
                            therefor, received by the Company since the Issue
                            Date as a contribution to its common equity capital
                            or from the issue, sale or exchange of Equity
                            Interests of the Company (other than Disqualified
                            Stock and except to the extent such net cash
                            proceeds are used to support the incurrence of new
                            Indebtedness pursuant to clause (9) of the second
                            paragraph of Section 4.09 hereof) or from the issue
                            or sale

                                      51
<PAGE>

                            (whether before or after the Issue Date) of
                            Disqualified Stock or debt securities of the Company
                            (including the Convertible Notes) that have been
                            converted after the Issue Date into Equity Interests
                            (other than Equity Interests (or Disqualified Stock
                            or convertible debt securities) sold to or held by a
                            Subsidiary of the Company and other than
                            Disqualified Stock or convertible debt securities
                            that have been converted into Disqualified Stock);
                            plus

                     (c)    to the extent that any Restricted Investment that
                            was made after the Issue Date is sold for cash or
                            otherwise liquidated or repaid for cash, the lesser
                            of:

                            (A)    the cash return of capital with respect to
                                   the Restricted Investment (less the cost of
                                   disposition, if any), and

                            (B)    the initial amount of the Restricted
                                   Investment; plus

                     (d)    to the extent that any Unrestricted Subsidiary of
                            the Company and all of its Subsidiaries are
                            designated as or become Restricted Subsidiaries
                            after the Issue Date, the lesser of:

                            (A)    the fair market value of the Company's
                                   Investments in such Subsidiaries as of the
                                   date they are designated or become Restricted
                                   Subsidiaries; or

                            (B)    the sum of:

                                   (x)    except in the case of Verestar and its
                                          Subsidiaries becoming Restricted
                                          Subsidiaries from Unrestricted
                                          Subsidiaries at a time when they have
                                          not previously been Restricted
                                          Subsidiaries of the Issuer, the fair
                                          market value of the Company's
                                          Investments in such Subsidiaries as of
                                          the date on which such Subsidiaries
                                          were most recently designated as
                                          Unrestricted Subsidiaries, and

                                   (y)    the amount of any Investments made in
                                          such Subsidiaries subsequent to such
                                          designation as Unrestricted
                                          Subsidiaries (and treated as
                                          Restricted Payments or excluded from
                                          clause (3)(b) pursuant to the second
                                          proviso of clause (2) of the next
                                          paragraph) by the Company or any
                                          Restricted Subsidiary; plus

                     (e)    100% of any dividends or other distributions
                            received by the Company or a Restricted Subsidiary
                            after the Issue Date from an

                                      52
<PAGE>

                            Unrestricted Subsidiary of the Company, to the
                            extent that such dividends were not otherwise
                            included in Consolidated Net Income of the Company
                            for such period.

       The preceding provisions shall not prohibit:

              (1)    the payment of any dividend or the making of any
                     distribution within 60 days after the date of declaration
                     of that dividend or distribution, if at said date of
                     declaration such payment or distribution would have
                     complied with the provisions of this Indenture;

              (2)    (a) the making of any Investment (including pursuant to
                     clause (a) or (b) in the first sentence of the definition
                     of Verestar Net Investment) or (b) the redemption,
                     repurchase, retirement, defeasance or other acquisition of
                     any subordinated Indebtedness or Equity Interests of the
                     Company, in the case of (a) or (b), in exchange for, or out
                     of the net cash proceeds (or in the case of an Investment
                     in Verestar or its Subsidiaries, other assets)
                     substantially concurrent sale after the Issue Date (other
                     than to a Subsidiary of the Company) of Equity Interests of
                     the Company (other than any Disqualified Stock); provided
                     that the net cash proceeds (or other assets, as applicable)
                     are not used to incur new Indebtedness pursuant to clause
                     (9) of the second paragraph of Section 4.09 hereof); and
                     provided further that, in each case, the amount of any net
                     cash proceeds (or other assets, as applicable) that are so
                     utilized will be excluded from clause (3)(b) of the
                     preceding paragraph;

              (3)    the defeasance, redemption, repurchase or other acquisition
                     of subordinated Indebtedness with the net cash proceeds
                     from an incurrence of Permitted Refinancing Indebtedness;

              (4)    the payment of any dividend by a Restricted Subsidiary of
                     the Company to the holders of its Equity Interests on a pro
                     rata basis; or

              (5)    the repurchase, redemption or other acquisition or
                     retirement for value of any Equity Interests of the Company
                     or any Restricted Subsidiary of the Company held by any
                     member of the Company's (or any of its Restricted
                     Subsidiaries') management pursuant to any management equity
                     subscription agreement, stockholder agreement, stock option
                     agreement or restricted stock agreement in effect as of the
                     Issue Date; provided that the aggregate price paid for all
                     of the repurchased, redeemed, acquired or retired Equity
                     Interests may not exceed

                     (a)    $500,000 in any twelve-month period, and

                     (b)    $5.0 million in the aggregate since the Issue Date.

                                      53
<PAGE>

       The Board of Directors may designate any Restricted Subsidiary to be an
Unrestricted Subsidiary if such designation would not cause a Default. For
purposes of making such determination, all outstanding Investments by the
Company and its Restricted Subsidiaries (except to the extent repaid in cash) in
the Subsidiary so designated will be deemed to be Restricted Payments at the
time of the designation and will reduce the amount available for Restricted
Payments under the first paragraph in this Section 4.07. All of those
outstanding Investments will be deemed to constitute Investments in an amount
equal to the fair market value of the Investments at the time of such
designation. Such designation will only be permitted if the Restricted Payment
would be permitted at the time and if the Restricted Subsidiary otherwise meets
the definition of an Unrestricted Subsidiary. The Board of Directors may
designate any Unrestricted Subsidiary to be a Restricted Subsidiary if the
designation would not cause a Default.

       The amount of all Restricted Payments (other than cash) will be the fair
market value on the date of the Restricted Payment of the assets or securities
proposed to be transferred or issued by the Company or the applicable Restricted
Subsidiary, as the case may be, pursuant to the Restricted Payment, except as
described in the next sentence. In the event the Company declares or pays an
Excepted Verestar Dividend, the amount of the Restricted Payment will be the
product of (a)(i) the Verestar Net Investment then outstanding that has been
made in reliance on clause (10) of the definition of "Permitted Investment",
reduced by (ii) the amount of Restricted Payments previously made in reliance on
this sentence, and (b) the percentage of the outstanding common stock or similar
Capital Stock of Verestar owned by the Company that is the subject of such
dividend or distribution. The fair market value of any property, assets or
Investments required by this covenant to be valued will be valued by the Board
of Directors whose resolution with respect to the determination will be
delivered to the Trustee.

       Section 4.08. Dividend and Other Payment Restrictions Affecting
Subsidiaries.

       The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, directly or indirectly, create or otherwise cause or suffer to
exist or become effective any encumbrance or restriction on the ability of any
Restricted Subsidiary to:

              (1)    pay dividends or make any other distributions to the
                     Company or any of its Restricted Subsidiaries on its
                     Capital Stock or with respect to any other interest or
                     participation in, or measured by, its profits;

              (2)    pay any Indebtedness owed to the Company or any of its
                     Restricted Subsidiaries;

              (3)    make loans or advances to the Company or any of its
                     Restricted Subsidiaries; or

              (4)    transfer any of its properties or assets to the Company or
                     any of its Restricted Subsidiaries.

                                      54
<PAGE>

       The preceding restrictions shall not apply to encumbrances or
restrictions existing under or by reason of:

              (1)    Existing Indebtedness as in effect on the Issue Date, and
                     any amendments, modifications, restatements, renewals,
                     increases, supplements, refundings, replacements or
                     refinancings thereof; provided that such amendments,
                     modifications, restatements, renewals, increases,
                     supplements, refundings, replacements or refinancings are
                     no more restrictive, taken as a whole, with respect to such
                     dividend and other payment restrictions than those
                     contained in the applicable series of Existing Indebtedness
                     as in effect on the Issue Date;

              (2)    Indebtedness of any Restricted Subsidiary under any Credit
                     Facility that is permitted to be incurred pursuant to
                     Section 4.09 hereof; provided that such Credit Facility and
                     Indebtedness contain only such encumbrances and
                     restrictions on such Restricted Subsidiary's ability to
                     engage in the activities set forth in clauses (1) through
                     (4) of the preceding paragraph as are, at the time such
                     Credit Facility is entered into or amended, modified,
                     restated, renewed, increased, supplemented, refunded,
                     replaced or refinanced, ordinary and customary for a Credit
                     Facility of that type as determined in the good faith
                     judgment of the Board of Directors (and evidenced in a
                     board resolution), which determination shall be
                     conclusively binding;

              (3)    encumbrances and restrictions applicable to any
                     Unrestricted Subsidiary, as the same are in effect as of
                     the date on which the Subsidiary becomes a Restricted
                     Subsidiary, and as the same may be amended, modified,
                     restated, renewed, increased, supplemented, refunded,
                     replaced or refinanced; provided that such amendments,
                     modifications, restatements, renewals, increases,
                     supplements, refundings, replacement or refinancings are no
                     more restrictive, taken as a whole, with respect to the
                     dividend and other payment restrictions than those
                     contained in the applicable series of Indebtedness of such
                     Subsidiary as in effect on the date on which such
                     Subsidiary becomes a Restricted Subsidiary;

              (4)    any Indebtedness incurred in compliance with Section 4.09
                     hereof or any agreement pursuant to which such Indebtedness
                     is issued if the encumbrance or restriction applies only in
                     the event of a payment default or default with respect to a
                     financial covenant contained in the Indebtedness or
                     agreement and the encumbrance or restriction is not
                     materially more disadvantageous to the Holders of the Notes
                     than is customary in comparable financings (as determined
                     by the Company) and the Company determines that any such
                     encumbrance or restriction will not materially affect the
                     Company's ability to pay interest or principal on the
                     Notes;

                                      55
<PAGE>

              (5)    this Indenture;

              (6)    applicable law;

              (7)    any instrument governing Indebtedness or Capital Stock of a
                     Person acquired by the Company or any of its Restricted
                     Subsidiaries as in effect at the time that Person is
                     acquired by the Company (except to the extent the
                     Indebtedness was incurred in connection with or in
                     contemplation of the acquisition), which encumbrance or
                     restriction is not applicable to any Person, or the
                     properties or assets of any Person, other than the Person,
                     or the property or assets of the Person, so acquired, and
                     as such instrument may be amended, modified, restated,
                     renewed, increased, supplemented, refunded, replaced or
                     refinanced, provided that, in the case of Indebtedness, the
                     Indebtedness was permitted by the terms hereof to be
                     incurred and, provided further, that any such amendment,
                     modification, restatement, renewal, increase, supplement,
                     refunding, replacement or refinancing is no more
                     restrictive, taken as a whole, with respect to the dividend
                     and other payment restrictions than those contained in the
                     instrument as in effect on the date on which the Person was
                     acquired by the Company;

              (8)    customary non-assignment provisions in leases or licenses
                     entered into in the ordinary course of business;

              (9)    purchase money obligations for property acquired in the
                     ordinary course of business that impose restrictions of the
                     nature described in clause (3) in the second paragraph of
                     Section 4.09 hereof on the property so acquired;

              (10)   any agreement for the sale of a Restricted Subsidiary that
                     restricts that Restricted Subsidiary pending its sale;

              (11)   Permitted Refinancing Indebtedness, provided that the
                     restrictions contained in the agreements governing the
                     Permitted Refinancing Indebtedness are no more restrictive,
                     taken as a whole, than those contained in the agreements
                     governing the Indebtedness being refinanced;

              (12)   Liens permitted to be incurred pursuant to the provisions
                     of Section 4.12 hereof that limit the right of the debtor
                     to transfer the assets subject to such Liens;

              (13)   provisions with respect to the disposition or distribution
                     of assets or property in joint venture agreements and other
                     similar agreements; and

              (14)   restrictions on cash or other deposits or net worth imposed
                     by customers under contracts entered into in the ordinary
                     course of business.

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<PAGE>

       Section 4.09. Incurrence of Indebtedness and Issuance of Preferred Stock.

       The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, directly or indirectly, create, incur, issue, assume, guarantee
or otherwise become directly or indirectly liable, contingently or otherwise,
with respect to (collectively, "incur") any Indebtedness (including Acquired
Debt) and the Company will not issue any Disqualified Stock and will not permit
any of its Restricted Subsidiaries to issue any shares of preferred stock;
provided that the Company may incur Indebtedness (including Acquired Debt) or
issue shares of Disqualified Stock and the Company's Restricted Subsidiaries may
incur Indebtedness (including Acquired Debt) or issue preferred stock if, in
each case, the Company's Debt to Adjusted Consolidated Cash Flow Ratio at the
time of incurrence of the Indebtedness or the issuance of the preferred stock,
after giving pro forma effect to such incurrence or issuance as of such date and
to the use of proceeds from such incurrence or issuance as if the same had
occurred at the beginning of the most recently ended four full fiscal quarter
period of the Company for which internal financial statements are available,
would have been no greater than 7.5 to 1.

       The provisions of the first paragraph of this Section 4.09 shall not
prohibit the incurrence of any of the following items of Indebtedness or to the
issuance of any of the following items of Disqualified Stock or preferred stock
(collectively, "Permitted Debt"):

              (1)    the incurrence by the Company or any of its Restricted
                     Subsidiaries of Indebtedness under the Credit Facilities
                     (including Credit Facilities also constituting Excepted
                     Verestar Debt) since the Issue Date in an aggregate
                     principal amount (with letters of credit being deemed to
                     have a principal amount equal to the maximum potential
                     liability of the Company and its Restricted Subsidiaries
                     thereunder) at any one time outstanding not to exceed the
                     greater of

                     (a)    $2.65 billion less any amount applied to reduce
                            Indebtedness under a Credit Facility pursuant to
                            clause (1) of the third paragraph of Section 4.10,
                            and

                     (b)    the sum of

                            (x)    product of $150,000 times the number of
                                   Completed Towers on the date of such
                                   incurrence; plus

                            (y)    the product of $1,000,000 times the number of
                                   Completed Broadcast Towers on the date of
                                   such incurrence; provided that the amount of
                                   Indebtedness permitted by this clause (y)
                                   does not exceed 25% of the cost of acquiring
                                   or constructing such Completed Broadcast
                                   Towers; plus

                            (z)    the product of 6.0 times Non-Tower Cash Flow
                                   on the date of such incurrence;

                                      57
<PAGE>

              (2)    the incurrence by the Company and its Restricted
                     Subsidiaries of the Existing Indebtedness;

              (3)    the incurrence by the Company or any of its Restricted
                     Subsidiaries of Indebtedness since the Issue Date

                     (a)    represented by Capital Lease Obligations incurred
                            (i) in connection with the lease or other use of
                            space or time on satellites or (ii) for the purpose
                            of financing all or any pat of the purchase price or
                            cost of construction or improvement of property,
                            plant or equipment, in each case used in the
                            Teleports Business of the Company or such Restricted
                            Subsidiary, or

                     (b)    represented by Capital Lease Obligations, mortgage
                            financings or purchase money obligations, in each
                            case incurred for the purpose of financing all or
                            any part of the purchase price or cost of
                            construction or improvement of property, plant or
                            equipment used in any business of the Company or
                            such Restricted Subsidiary, in an aggregate
                            principal amount for purposes of this clause (3)(b),
                            including all Permitted Refinancing Indebtedness
                            incurred to refund, refinance or replace any other
                            Indebtedness incurred pursuant to this clause
                            (3)(b), not to exceed $50.0 million at any one time
                            outstanding;

              (4)    the incurrence by the Company or any of its Restricted
                     Subsidiaries of Permitted Refinancing Indebtedness in
                     exchange for, or the net proceeds of which are used to
                     extend, refinance, renew, replace, defease or refund
                     Indebtedness of the Company or any of its Restricted
                     Subsidiaries or Disqualified Stock of the Company (other
                     than intercompany Indebtedness) that was permitted by this
                     Indenture to be incurred under the first paragraph of this
                     Section 4.09 or clause (2) or (3) or this clause (4) of
                     this paragraph;

              (5)    the incurrence by the Company or any of its Restricted
                     Subsidiaries of intercompany Indebtedness between or among
                     the Company and any of its Restricted Subsidiaries and the
                     issuance by any Restricted Subsidiary of the Company of
                     shares of preferred stock to the Company or another
                     Restricted Subsidiary of the Company; provided, however,
                     that if the Company is the obligor on such Indebtedness,
                     such Indebtedness is expressly subordinated to the prior
                     payment in full in cash of all obligations with respect to
                     the Notes of such series and that:

                     (a)    any subsequent issuance or transfer of Equity
                            Interests that results in any such Indebtedness or
                            preferred stock being held by a Person other than
                            the Company or a Restricted Subsidiary, and

                                      58
<PAGE>

                     (b)    any sale or other transfer of any such Indebtedness
                            or preferred stock to a Person that is not either
                            the Company or a Restricted Subsidiary,

                     shall be deemed, in each case, to constitute an incurrence
                     of the Indebtedness by the Company or the Restricted
                     Subsidiary or the issuance of the shares of preferred stock
                     by the Restricted Subsidiary, as the case may be;

              (6)    the incurrence by the Company or any of its Restricted
                     Subsidiaries of Hedging Obligations that are incurred for
                     the purpose of fixing or hedging interest rate risk with
                     respect to any floating rate Indebtedness that is permitted
                     by the terms of this Indenture to be outstanding or
                     currency exchange risk;

              (7)    the guarantee by the Company or any of its Restricted
                     Subsidiaries of Indebtedness of the Company or a Restricted
                     Subsidiary of the Company that was permitted to be incurred
                     by another provision of this Indenture;

              (8)    the incurrence by the Company or any of its Restricted
                     Subsidiaries of Acquired Debt in connection with a merger
                     with or into a Restricted Subsidiary, the acquisition of
                     assets or a new Subsidiary and the incurrence by the
                     Company's Restricted Subsidiaries of Indebtedness as a
                     result of the designation of an Unrestricted Subsidiary as
                     a Restricted Subsidiary; provided that, in the case of any
                     such incurrence of Acquired Debt, such Acquired Debt was
                     incurred by the prior owner of such assets or such
                     Restricted Subsidiary prior to such acquisition by the
                     Company or one of its Restricted Subsidiaries and was not
                     incurred in connection with, or in contemplation of, the
                     acquisition by the Company or one of its Restricted
                     Subsidiaries; and provided further that, in the case of any
                     incurrence pursuant to this clause (8), as a result of such
                     acquisition by the Company or one of its Restricted
                     Subsidiaries, the Company's Debt to Adjusted Consolidated
                     Cash Flow Ratio at the time of incurrence of such Acquired
                     Debt, after giving pro forma effect to such acquisition and
                     incurrence as if the same had occurred at the beginning of
                     the most recently ended four full fiscal quarter period of
                     the Company for which internal financial statements are
                     available, would have been less than the Company's Debt to
                     Adjusted Consolidated Cash Flow Ratio for the same period
                     without giving pro forma effect to such incurrence;

              (9)    the incurrence by the Company of Indebtedness or
                     Disqualified Stock not to exceed, at any one time
                     outstanding, the sum of:

                     (i)    2.0 times the aggregate net cash proceeds, plus

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<PAGE>

                     (ii)   1.0 times the fair market value of non-cash proceeds
                            (evidenced by a resolution of the Board of Directors
                            set forth in an Officers' Certificate delivered to
                            the Trustee),

                            in each case, from the issuance and sale, other than
                            to a Subsidiary, of Equity Interests (other than
                            Disqualified Stock and excluding conversion of the
                            Convertible Notes) of the Company since the Issue
                            Date (less the amount of such proceeds used to make
                            Restricted Payments as provided in clause (3)(b) of
                            the first paragraph or clause (2) of the second
                            paragraph of Section 4.07 hereof);

              (10)   the incurrence by the Company or any of its Restricted
                     Subsidiaries since the Issue Date of additional
                     Indebtedness and/or the issuance by the Company of
                     Disqualified Stock in an aggregate principal amount,
                     accreted value or liquidation preference, as applicable, at
                     any time outstanding, not to exceed $25.0 million; and

              (11)   the incurrence by the Company's Restricted Subsidiaries of
                     Excepted Verestar Debt as a result of Verestar's and its
                     Subsidiaries' becoming Restricted Subsidiaries of the
                     Company, but only to the extent such Indebtedness could not
                     have been incurred under any other provision of this
                     Section 4.09.

       In addition, the Company shall not:

              (1)    incur any Indebtedness that is contractually subordinated
                     in right of payment to any other Indebtedness of the
                     Company unless such Indebtedness is also contractually
                     subordinated in right of payment to the Notes on
                     substantially identical terms; provided, however, that no
                     Indebtedness of the Company will be deemed to be
                     contractually subordinated in right of payment to any other
                     Indebtedness of the Company solely by virtue of being
                     unsecured;

              (2)    permit Verestar and its Subsidiaries, at any time when they
                     have Special Verestar Status, to incur any Indebtedness
                     other than Excepted Verestar Debt; and

              (3)    permit any of its Unrestricted Subsidiaries (including
                     Verestar and its Subsidiaries at a time when they are
                     Unrestricted Subsidiaries but to not have Special Verestar
                     Status) to incur any Indebtedness other than Non-Recourse
                     Debt or Indebtedness owed to the Company or its Restricted
                     Subsidiaries.

       For purposes of determining compliance with this Section 4.09, in the
event that an item of Indebtedness meets the criteria of more than one of the
categories of Permitted Debt described

                                      60
<PAGE>

in clauses (1) through (11) above or is entitled to be incurred pursuant to the
first paragraph of this Section 4.09, the Company shall, except as otherwise
provided in clause (11) above, in its sole discretion classify (or later
reclassify in whole or in part) such item of Indebtedness in any manner that
complies with this Section 4.09. Accrual of interest, accretion or amortization
of original issue discount and the payment of interest in the form of additional
Indebtedness shall not be deemed to be an incurrence of Indebtedness for
purposes of this Section 4.09.

       Section 4.10. Asset Sales.

       The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, consummate an Asset Sale unless:

              (1)    the Company (or the Restricted Subsidiary, as the case may
                     be) receives consideration at the time of the Asset Sale at
                     least equal to the fair market value of the assets or
                     Equity Interests issued or sold or otherwise disposed of;

              (2)    fair market value is determined by the Board of Directors
                     and evidenced by a resolution of the Board of Directors set
                     forth in an Officers' Certificate delivered to the Trustee;
                     and

              (3)    except in the case of a Tower Asset Exchange, a Surplus
                     Asset Sale, an Excluded International Sale or an Excepted
                     Verestar Sale, at least 75% of the consideration received
                     in such Asset Sale by the Company or such Restricted
                     Subsidiary is in the form of cash or Cash Equivalents.

       For purposes of this provision, each of the following shall be deemed to
be cash:

              (a)    any liabilities, as shown on the Company's or such
                     Restricted Subsidiary's most recent balance sheet, of the
                     Company's or any Restricted Subsidiary (other than
                     contingent liabilities and liabilities that are by their
                     terms subordinated to the Notes or any guarantee of the
                     Notes) that are assumed by the transferee of any assets
                     pursuant to a customary novation agreement that releases
                     the Company or the Restricted Subsidiary from further
                     liability; and

              (b)    any securities, notes or other obligations received by the
                     Company or any Restricted Subsidiary from the transferee
                     that are converted by the Company or the Restricted
                     Subsidiary into cash within 20 days of the applicable Asset
                     Sale, to the extent of the cash received in that
                     conversion.

       Within 365 days after the receipt of any Net Proceeds from an Asset Sale
by the Company or a Restricted Subsidiary of the Company, the Company or the
Restricted Subsidiary may apply those Net Proceeds to:

              (1)    reduce Indebtedness under a Credit Facility;

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<PAGE>

              (2)    reduce other Indebtedness of any of the Restricted
                     Subsidiaries;

              (3)    acquire assets other than Voting Stock;

              (4)    acquire Voting Stock or other Equity Interests of a Person
                     that is not a Subsidiary of the Company; provided that,
                     after giving effect to the acquisition, such Person becomes
                     a Subsidiary of the Company or its Restricted Subsidiary;
                     or

              (5)    make a capital expenditure.

       Pending the final application of any Net Proceeds, the Company may
temporarily reduce revolving credit borrowings or otherwise invest the Net
Proceeds in any manner that is not prohibited by this Indenture.

       Any Net Proceeds from Asset Sales that are not applied or invested as
provided in the preceding paragraph shall be deemed to constitute "Excess
Proceeds". When the aggregate amount of Excess Proceeds exceeds $10.0 million,
the Company shall make an Asset Sale Offer to all Holders of Notes, and all
holders of other unsubordinated Indebtedness of the Company containing
provisions similar to those set forth in this Indenture with respect to offers
to purchase or redeem with the proceeds of sales of assets, to purchase the
maximum principal amount of Notes and such other unsubordinated Indebtedness of
the Company that may be purchased out of the Excess Proceeds. The offer price in
any Asset Sale Offer will be payable in cash and will be 100% of the principal
amount of the Notes, plus accrued and unpaid interest to the date of purchase,
if any. In the case of any other unsubordinated Indebtedness, the offer price
shall be 100% of the principal amount (or accreted value, as applicable) of the
Indebtedness plus accrued and unpaid interest thereon, if any, to the date of
purchase. Each Asset Sale Offer shall be made in accordance with the procedures
set forth herein and the other unsubordinated Indebtedness of the Company. If
any Excess Proceeds remain after consummation of an Asset Sale Offer, the
Company may use the remaining Excess Proceeds for any purpose not otherwise
prohibited by this Indenture. If the aggregate principal amount, as applicable,
of Notes and the other senior Indebtedness of the Company tendered into the
Asset Sale Offer exceeds the amount of Excess Proceeds, the Trustee shall select
the Notes and such other unsubordinated Indebtedness to be purchased on a pro
rata basis. Upon completion of the Asset Sale Offer, the amount of Excess
Proceeds shall be reset at zero.

       The provisions under this Indenture relating to the Company's obligation
to make an offer to repurchase the Notes as a result of an Asset Sale may be
waived or modified with the written consent of the Holders of at least a
majority in principal amount of the Notes then outstanding.

       Section 4.11. Transactions with Affiliates.

       The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, make any payment to, or sell, lease, transfer or otherwise
dispose of any of its properties or assets to, or purchase any property or
assets from, or enter into or make or amend any transaction, contract,

                                      62
<PAGE>

agreement, understanding, loan, advance or guarantee with, or for the benefit
of, any Affiliate (each of the foregoing, an "Affiliate Transaction"), unless:

              (1)    such Affiliate Transaction is on terms that, in the
                     aggregate, are no less favorable to the Company or the
                     relevant Restricted Subsidiary than those that would have
                     been obtained in a comparable transaction by the Company or
                     such Restricted Subsidiary with an unrelated Person; and

              (2)    the Company delivers to the Trustee:

                     (a)    with respect to any Affiliate Transaction or series
                            of related Affiliate Transactions involving
                            aggregate consideration in excess of $5.0 million,
                            an Officers' Certificate certifying that the
                            Affiliate Transaction complies with clause (1)
                            above;

                     (b)    with respect to any Affiliate Transaction or series
                            of related Affiliate Transactions involving
                            aggregate consideration in excess of $10.0 million,
                            a resolution of the Board of Directors set forth in
                            an Officers' Certificate certifying that the
                            Affiliate Transaction complies with clause (1) above
                            and that the Affiliate Transaction has been approved
                            by a majority of the members of the full Board of
                            Directors (not only a committee thereof) having no
                            personal stake in such Affiliate Transaction (or, if
                            there are no such members, by all of the members of
                            the full Board of Directors and by the procedure
                            described in clause (c) below);

                     (c)    with respect to any Affiliate Transaction or series
                            of related Affiliate Transactions involving an
                            aggregate consideration in excess of $25.0 million,
                            other than a Permitted Investment, an opinion to the
                            Holders of the Notes as to the fairness of the
                            Affiliate Transaction from a financial point of view
                            issued by an accounting, appraisal or investment
                            banking firm of national standing.

       Notwithstanding the foregoing, the following items shall not be deemed
Affiliate Transactions:

              (1)    any employment arrangements with any executive officer of
                     the Company or a Restricted Subsidiary that is entered into
                     by the Company or any of its Restricted Subsidiaries in the
                     ordinary course of business and substantially consistent
                     with compensation arrangements of similarly situated
                     executive officers at comparable companies engaged in
                     Permitted Businesses;

              (2)    transactions between or among the Company and/or its
                     Restricted Subsidiaries;

                                      63
<PAGE>

              (3)    payment of directors' fees (in cash or other property) in
                     an aggregate annual amount per Person that is substantially
                     consistent with directors' fees at comparable companies
                     engaged in Permitted Businesses;

              (4)    Restricted Payments that are permitted under Section 4.07
                     hereof;

              (5)    the issuance or sale of Equity Interests (other than
                     Disqualified Stock) of the Company; and

              (6)    transactions pursuant to the Tax Sharing Agreement.

       Section 4.12. Liens.

       The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, directly or indirectly, create, incur, assume or suffer to
exist any Lien securing Indebtedness or trade payables on any asset now owned or
hereafter acquired, or any income or profits therefrom or assign or convey as
security any right to receive income therefrom, except Permitted Liens.

       Section 4.13. Corporate Existence.

       Subject to Article 5 hereof, the Company shall do or cause to be done all
things necessary to preserve and keep in full force and effect:

              (1)    its corporate existence, and the corporate, partnership or
                     other existence of each of its Subsidiaries, in accordance
                     with the respective organizational documents (as the same
                     may be amended from time to time) of the Company or any
                     such Subsidiary and

              (2)    the rights (charter and statutory), licenses and franchises
                     of the Company and its Subsidiaries;

provided, however, that the Company shall not be required to preserve any such
right, license or franchise, or the corporate, partnership or other existence of
any of its Subsidiaries, if the Board of Directors shall determine that the
preservation thereof is no longer desirable in the conduct of the business of
the Company and its Subsidiaries, taken as a whole, and that the loss thereof is
not adverse in any material respect to the Holders of the Notes.

       Section 4.14. Offer to Repurchase Upon Change of Control.

       If a Change of Control occurs, the Company shall make an offer (a "Change
of Control Offer") to each Holder to repurchase all or any part (equal to $1,000
or an integral multiple thereof) of each Holder's Notes at a purchase price, in
cash, equal to 101% of the aggregate principal amount of the Notes repurchased,
plus accrued and unpaid interest thereon, if any, (subject to the right of
Holders of record on the relevant record date to receive interest due on the
relevant interest payment date), to the date of purchase (the "Change of Control
Payment").

                                      64
<PAGE>

Within 30 days following any Change of Control, the Company shall mail a notice
to each Holder describing the transaction or transactions that constitute a
Change of Control and stating:

              (1)    that the Change of Control Offer is being made pursuant to
                     this covenant and that all Notes tendered will be accepted
                     for payment;

              (2)    the purchase price and the purchase date, which shall be no
                     earlier than 30 days and no later than 60 days from the
                     date such notice is mailed (the "Change of Control Payment
                     Date");

              (3)    that any Note not tendered will continue to accrue
                     interest;

              (4)    that, unless the Company defaults in the payment of the
                     Change of Control Payment, all Notes accepted for payment
                     pursuant to the Change of Control Offer shall cease to
                     accrue interest after the Change of Control Payment Date;

              (5)    that Holders electing to have any Notes purchased pursuant
                     to a Change of Control Offer will be required to surrender
                     the Notes, with the form entitled "Option of Holder to
                     Elect Purchase" on the reverse of the Notes completed, to
                     the Paying Agent at the address specified in the notice
                     prior to the close of business on the third Business Day
                     preceding the Change of Control Payment Date;

              (6)    that Holders will be entitled to withdraw their election if
                     the Paying Agent receives, not later than the close of
                     business on the second Business Day preceding the Change of
                     Control Payment Date, a telegram, telex, facsimile
                     transmission or letter setting forth the name of the
                     Holder, the principal amount of Notes delivered for
                     purchase, and a statement that such Holder is withdrawing
                     his election to have the Notes purchased;

              (7)    that Holders whose Notes are being purchased only in part
                     will be issued new Notes equal in principal amount to the
                     unpurchased portion of the Notes surrendered, which
                     unpurchased portion must be equal to $1,000 in principal
                     amount or an integral multiple thereof; and

              (8)    that Holders electing to have a Note purchased pursuant to
                     a Change of Control Offer may elect to have Notes purchased
                     in integral multiples of $1,000 only.

       On the Change of Control Payment Date, the Company shall, to the extent
lawful,

              (1)    accept for payment all Notes or portions of the Notes
                     properly tendered pursuant to the Change of Control Offer;

                                      65
<PAGE>

              (2)    deposit with the Paying Agent an amount equal to the Change
                     of Control Payment in respect of all Notes or portions of
                     the Notes so tendered; and

              (3)    deliver or cause to be delivered to the Trustee the Notes
                     so accepted together with an Officers' Certificate stating
                     the aggregate principal amount of Notes or portions thereof
                     being purchased by the Company.

       The Paying Agent shall promptly mail to each Holder of Notes properly
tendered payment in an amount equal to the Change of Control Payment with
respect to the purchased Notes, and the Trustee shall promptly authenticate and
mail (or cause to be transferred by book entry) to each Holder a new Note equal
in principal amount to any unpurchased portion of the Notes surrendered by such
Holder, if any; provided, however, that each such new Note shall be in a
principal amount of $1,000 or an integral multiple thereof. The Company shall
publicly announce the results of the Change of Control Offer on or as soon as
practicable after the Change of Control Payment Date.

       The Change of Control provisions described above shall be applicable
whether or not any other provisions of this Indenture are applicable. The
Company shall comply with the requirements of Section 14(e) of the Exchange Act
and any other securities laws or regulations to the extent those laws and
regulations are applicable to any Change of Control Offer. If the provisions of
any of the applicable securities laws or securities regulations conflict with
the provisions of this Section 4.14, the Company shall comply with the
applicable securities laws and regulations and shall not be deemed to have
breached its obligations under this Section 4.14 by virtue of the compliance.

       The Company shall not be required to make a Change of Control Offer upon
a Change of Control if a third party makes the Change of Control Offer in the
manner, at the times and otherwise in compliance with the requirements set forth
in this Indenture applicable to a Change of Control Offer made by the Company
and purchases all Notes properly tendered and not withdrawn under such Change of
Control Offer. The provisions under this Indenture relating to the Company's
obligation to make an offer to repurchase the Notes as a result of a Change of
Control may be waived or modified with the written consent of the Holders of at
least a majority in principal amount of the Notes then outstanding.

       Section 4.15. Sale and Leaseback Transactions.

       The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, enter into any sale and leaseback transaction; provided,
however, that the Company or any of its Restricted Subsidiaries may enter into a
sale and leaseback transaction if:

              (1)    the Company or such Restricted Subsidiary, as applicable,
                     could have:

                     (a)    incurred Indebtedness in an amount equal to the
                            Attributable Debt relating to such sale and
                            leaseback transaction pursuant to the Debt

                                      66
<PAGE>

                            to Adjusted Consolidated Cash Flow Ratio test set
                            forth in the first paragraph of Section 4.09 hereof;
                            or

                     (b)    incurred a Lien to secure such Indebtedness pursuant
                            to the provisions of Section 4.12 hereof;

              (2)    the gross cash proceeds of such sale and leaseback
                     transaction are at least equal to the fair market value (as
                     determined in good faith by the Board of Directors) of the
                     property that is the subject of the sale and leaseback
                     transaction; and

              (3)    the transfer of assets in the sale and leaseback
                     transaction is permitted by, and the Company applies the
                     proceeds of such transaction in compliance with, Section
                     4.10 hereof.

       Section 4.16. Limitation on Issuances and Sales of Capital Stock of
Restricted Subsidiaries.

       The Company:

              (1)    shall not, and shall not permit any of its Restricted
                     Subsidiaries to, transfer, convey, sell, lease or otherwise
                     dispose of any Equity Interests in any Restricted
                     Subsidiary of the Company to any Person (other than the
                     Company or a Wholly Owned Restricted Subsidiary of the
                     Company); and

              (2)    shall not permit any of its Restricted Subsidiaries to
                     issue any of its Equity Interests (other than, if
                     necessary, shares of its Capital Stock constituting
                     directors' qualifying shares) to any Person other than to
                     the Company or a Wholly Owned Restricted Subsidiary of the
                     Company,

       unless, in each such case:

                     (a)    as a result of such transfer, conveyance, sale,
                            lease or other disposition or issuance, such
                            Restricted Subsidiary no longer constitutes a
                            Subsidiary; and

                     (b)    the cash Net Proceeds from such transfer,
                            conveyance, sale, lease or other disposition or
                            issuance are applied in accordance with Section 4.10
                            hereof.

       Notwithstanding the foregoing, the issuance or sale of shares of Capital
Stock of any Restricted Subsidiary of the Company will not violate the
provisions of the immediately preceding sentence if such shares are issued or
sold in connection with

                     (w)    an Excepted Verestar Sale or an Excluded
                            International Sale,

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<PAGE>

                     (x)    the formation or capitalization of a Restricted
                            Subsidiary,

                     (y)    a single transaction or a series of substantially
                            contemporaneous transactions whereby such Restricted
                            Subsidiary becomes a Restricted Subsidiary of the
                            Company by reason of the acquisition of securities
                            or assets from another Person, or

                     (z)    the issuance by a Restricted Subsidiary of the
                            Company of Capital Stock to the holders of its
                            Capital Stock pursuant to pre-emptive or similar
                            rights (i) under applicable law or regulation, (ii)
                            contained in the instrument governing such Capital
                            Stock or (iii) pursuant to an agreement entered into
                            in connection with a transaction exempted pursuant
                            to clauses (x) or (y) above.

       Section 4.17. Limitation on Issuances of Guarantees of Indebtedness.

       The Company shall not permit any Restricted Subsidiary, directly or
indirectly, to Guarantee or pledge any assets to secure the payment of any other
Indebtedness of the Company (other than Indebtedness relating to a Credit
Facility) unless such Subsidiary simultaneously executes and delivers a
supplemental indenture to this Indenture governing the Notes providing for the
Guarantee of the payment of the Notes by such Subsidiary (a "Note Guarantee"),
which Note Guarantee shall be senior to or pari passu with such Subsidiary's
Guarantee of or pledge to secure such other Indebtedness. Notwithstanding the
foregoing, any Note Guarantee by a Subsidiary shall provide by its terms that it
shall be automatically and unconditionally released and discharged upon any
sale, exchange or transfer, to any Person other than a Subsidiary of the
Company, of all of the Company's stock in, or all or substantially all the
assets of, such Subsidiary, which sale, exchange or transfer is made in
compliance with the applicable provisions of this Indenture. The form of such
Note Guarantee is attached as Exhibit C hereto.

       Section 4.18. Covenant Suspension.

       During any period of time that:

              (a)    the Notes have Investment Grade Ratings from both Rating
                     Agencies and

              (b)    no Default or Event of Default has occurred and is
                     continuing under the Indenture,

the Company and the Restricted Subsidiaries will not be subject to the following
Sections of the Indenture: Section 3.09, Section 4.07, Section 4.08, Section
4.09, Section 4.10, Section 4.16, Section 4.17, clause (1)(a) of Section 4.15,
clause (1) of the proviso to the last paragraph of the definition of
"Unrestricted Subsidiary" in Section 1.01, and clause (2)(d) of Section 5.01
(collectively, the "Suspended Covenants"). In the event that the Company and its
Restricted Subsidiaries are not subject to the Suspended Covenants for any
period of time as a result of the preceding sentence and, subsequently, one or
both of the Rating Agencies withdraws its rating or downgrades the rating
assigned to the Notes below the required Investment Grade Rating or a

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Default or Event of Default occurs and is continuing, then the Company and its
Restricted Subsidiaries will thereafter again be subject to the Suspended
Covenants for all periods during the continuance of that withdrawal, downgrade,
Default or Event of Default and, furthermore, compliance with the provisions of
Section 4.07 with respect to Restricted Payments made after the time of the
withdrawal, downgrade, Default or Event of Default will be calculated in
accordance with the terms of that covenant as though that covenant had been in
effect during the entire period of time from the Issue Date, provided, however,
that there will not be deemed to have occurred a Default or Event of Default
with respect to the Suspended Covenants during the time that the Company and its
Restricted Subsidiaries were not subject to the Suspended Covenants (or after
that time based solely on events that occurred during that time).

                                   ARTICLE 5

                                   SUCCESSORS

       Section 5.01. Merger, Consolidation, or Sale of Assets.

       The Company shall not:

              (1)    consolidate or merge with or into (whether or not the
                     Company is the surviving corporation); or

              (2)    sell, assign, transfer, lease, convey or otherwise dispose
                     of all or substantially all of its properties or assets in
                     one or more related transactions, to another corporation,
                     Person or entity, unless:

                     (a)    either (A) the Company is the surviving corporation;
                            or (B) the entity or the Person formed by or
                            surviving any such consolidation or merger (if other
                            than the Company) or to which the sale, assignment,
                            transfer, lease, conveyance or other disposition
                            shall have been made is a corporation organized or
                            existing under the laws of the United States, any
                            state thereof or the District of Columbia;

                     (b)    the entity or Person formed by or surviving any such
                            consolidation or merger (if other than the Company)
                            or the entity or Person to which the sale,
                            assignment, transfer, lease, conveyance or other
                            disposition shall have been made assumes all the
                            Obligations of the Company under the Notes and this
                            Indenture pursuant to a supplemental indenture in a
                            form reasonably satisfactory to the Trustee;

                     (c)    immediately after such transaction no Default
                            exists; and

                     (d)    except in the case of (A) a merger of the Company
                            with or into a Wholly Owned Restricted Subsidiary of
                            the Company and (B) a

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                            merger entered into solely for the purpose of
                            reincorporating the Company in another jurisdiction:

                            (x)    in the case of a merger or consolidation in
                                   which the Company is the surviving
                                   corporation, the Company, at the time of the
                                   transaction, after giving pro forma effect to
                                   the transaction as of such date for balance
                                   sheet purposes and as if the transaction had
                                   occurred at the beginning of the most
                                   recently ended four full fiscal quarter
                                   period of the Company for which internal
                                   financial statements are available for income
                                   statement purposes, (i) would have been
                                   permitted to incur at least $1.00 of
                                   additional Indebtedness pursuant to the first
                                   paragraph of Section 4.09 hereof or (ii)
                                   would have had a Debt to Adjusted Cash Flow
                                   Ratio that was not greater than the Company's
                                   Debt to Adjusted Consolidated Cash Flow Ratio
                                   for the same period without giving pro forma
                                   effect to such transaction, or

                            (y)    in the case of any other such transaction,
                                   the entity or Person formed by or surviving
                                   any such consolidation or merger (if other
                                   than the Company), or to which the sale,
                                   assignment, transfer, lease, conveyance or
                                   other disposition shall have been made, at
                                   the time of the transaction, after giving pro
                                   forma effect to the transaction as of such
                                   date for balance sheet purposes and as if
                                   such transaction had occurred at the
                                   beginning of the most recently ended four
                                   full fiscal quarter period of such entity or
                                   Person for which internal financial
                                   statements are available for income statement
                                   purposes, (i) would have been permitted to
                                   incur at least $1.00 of additional
                                   Indebtedness pursuant to the first paragraph
                                   of Section 4.09 hereof or (ii) would have had
                                   a Debt to Adjusted Consolidated Cash Flow
                                   Ratio that was not greater than the Company's
                                   Debt to Adjusted Consolidated Cash Flow Ratio
                                   for the same period without giving pro forma
                                   effect to such transaction; provided,
                                   however, that for purposes of determining the
                                   amount of Indebtedness permitted to be
                                   incurred or the Debt to Adjusted Consolidated
                                   Cash Flow Ratio of any entity or Person for
                                   purposes of this clause (y) the entity or
                                   Person will be substituted for the Company in
                                   Section 4.09 hereof and in the definition of
                                   Debt to Adjusted Consolidated Cash Flow Ratio
                                   and the defined terms included therein under
                                   Section 1.01 hereof.

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       Section 5.02. Successor Corporation Substituted.

       Upon any consolidation or merger, or any sale, assignment, transfer,
lease, conveyance or other disposition of all or substantially all of the assets
of the Company in accordance with Section 5.01 hereof, the successor corporation
formed by such consolidation or into or with which the Company is merged or to
which such sale, assignment, transfer, lease, conveyance or other disposition is
made shall succeed to, and be substituted for (so that from and after the date
of such consolidation, merger, sale, lease, conveyance or other disposition, the
provisions of this Indenture referring to the "Company" shall refer instead to
the successor corporation and not to the Company), and may exercise every right
and power of the Company under this Indenture with the same effect as if such
successor Person had been named as the Company herein; provided, however, that
the predecessor Company shall not be relieved from the obligation to pay the
principal of and interest on the Notes except in the case of a sale of all of
the Company's assets that meets the requirements of Section 5.01 hereof.

                                   ARTICLE 6

                              DEFAULTS AND REMEDIES

       Section 6.01. Events of Default.

       Each of the following constitutes an Event of Default:

              (1)    default for 30 days in the payment when due of interest on
                     the Notes;

              (2)    default in payment when due of the principal of or premium,
                     if any, on the Notes;

              (3)    failure by the Company or any of its Subsidiaries to comply
                     with the provisions described under Article 5 hereof or
                     failure by the Company to consummate a Change of Control
                     Offer or Asset Sale Offer in accordance with the provisions
                     of this Indenture;

              (4)    failure by the Company or any of its Subsidiaries for 30
                     days after notice by the Trustee or the Holders of at least
                     25% in aggregate principal amount of the Notes then
                     outstanding, to comply with any of its other agreements in
                     this Indenture or the Notes;

              (5)    default under any mortgage, indenture or instrument under
                     which there may be issued or by which there may be secured
                     or evidenced any Indebtedness for money borrowed by the
                     Company or any of its Significant Subsidiaries (or the
                     payment of which is Guaranteed by the Company or any of its
                     Significant Subsidiaries) whether such Indebtedness or
                     Guarantee now exists, or is created after the date of this
                     Indenture, which default:

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                     (a)    is caused by a failure to pay principal of or
                            premium, if any, or interest on the Indebtedness
                            prior to the expiration of the grace period provided
                            in such Indebtedness on the date of the default (a
                            "Payment Default"); or

                     (b)    results in the acceleration of the Indebtedness
                            prior to its express maturity

                     and, in each case referred to in clause (a) and (b) above,
                     the principal amount of any such Indebtedness, together
                     with the principal amount of any other such Indebtedness
                     under which there has been a Payment Default or the
                     maturity of which has been so accelerated, aggregates $20.0
                     million or more;

              (6)    failure by the Company or any of its Significant
                     Subsidiaries to pay final judgments aggregating in excess
                     of $20.0 million, which judgments are not paid, discharged
                     or stayed for a period of 60 days; or

              (7)    the Company or any of its Significant Subsidiaries pursuant
                     to or within the meaning of Bankruptcy Law:

                     (a)    commences a voluntary case,

                     (b)    consents to the entry of an order for relief against
                            it in an involuntary case,

                     (c)    consents to the appointment of a custodian of it or
                            for all or substantially all of its property,

                     (d)    makes a general assignment for the benefit of its
                            creditors, or

                     (e)    generally is not paying its debts as they become
                            due; or

              (8)    a court of competent jurisdiction enters an order or decree
                     under any Bankruptcy Law that:

                     (a)    is for relief against the Company or any of its
                            Significant Subsidiaries in an involuntary case;

                     (b)    appoints a custodian of the Company or any of its
                            Significant Subsidiaries or for all or substantially
                            all of the property of the Company or any of its
                            Significant Subsidiaries; or

                     (c)    orders the liquidation of the Company or any of its
                            Significant Subsidiaries;

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                            and the order or decree remains unstayed and in
                            effect for 60 consecutive days.

       Section 6.02. Acceleration.

       If any Event of Default occurs and is continuing, the Trustee or the
Holders of at least 25% in principal amount of the then outstanding Notes may
declare all the Notes to be due and payable immediately. Upon any such
declaration, the principal of, and accrued and unpaid interest if any, on such
Notes shall become due and payable immediately. Notwithstanding the foregoing,
if an Event of Default specified in clause (7) or (8) of Section 6.01 hereof
occurs with respect to the Company or any of its Significant Subsidiaries, all
outstanding Notes shall be due and payable immediately without further action or
notice. The Holders of a majority in aggregate principal amount of the then
outstanding Notes by written notice to the Trustee may on behalf of all of the
Holders rescind an acceleration and its consequences if the rescission would not
conflict with any judgment or decree and if all existing Events of Default
(except nonpayment of principal, interest or premium that has become due solely
because of the acceleration) have been cured or waived.

       Section 6.03. Other Remedies.

       If an Event of Default occurs and is continuing, the Trustee may pursue
any available remedy to collect the payment of principal of, premium, if any,
and interest on the Notes or to enforce the performance of any provision of the
Notes or this Indenture.

       The Trustee may maintain a proceeding even if it does not possess any of
the Notes or does not produce any of them in the proceeding. A delay or omission
by the Trustee or any Holder of a Note in exercising any right or remedy
accruing upon an Event of Default shall not impair the right or remedy or
constitute a waiver of or acquiescence in the Event of Default. All remedies are
cumulative to the extent permitted by law.

       Section 6.04. Waiver of Past Defaults.

       Holders of not less than a majority in aggregate principal amount of the
then outstanding Notes by notice to the Trustee may on behalf of the Holders of
all of the Notes waive an existing Default or Event of Default and its
consequences hereunder, except a continuing Default or Event of Default in the
payment of the principal of, premium, if any, or interest on, the Notes
(including in connection with an offer to purchase) (provided, however, that the
Holders of a majority in aggregate principal amount of the then outstanding
Notes may rescind an acceleration and its consequences, including any related
payment default that resulted from such acceleration). Upon any such waiver,
such Default shall cease to exist, and any Event of Default arising therefrom
shall be deemed to have been cured for every purpose of this Indenture; but no
such waiver shall extend to any subsequent or other Default or impair any right
consequent thereon.

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<PAGE>

       Section 6.05. Control by Majority.

       Holders of a majority in principal amount of the then outstanding Notes
may direct the time, method and place of conducting any proceeding for
exercising any remedy available to the Trustee or exercising any trust or power
conferred on it. However, the Trustee may refuse to follow any direction that
conflicts with law or this Indenture, that the Trustee determines may be unduly
prejudicial to the rights of other Holders of Notes or that may involve the
Trustee in personal liability.

       Section 6.06. Limitation on Suits.

       A Holder of a Note may pursue a remedy with respect to this Indenture or
the Notes only if:

              (1)    the Holder of a Note gives to the Trustee written notice of
                     a continuing Event of Default;

              (2)    the Holders of at least 25% in principal amount of the then
                     outstanding Notes make a written request to the Trustee to
                     pursue the remedy;

              (3)    such Holder of a Note or Holders of Notes offer and, if
                     requested, provide to the Trustee indemnity satisfactory to
                     the Trustee against any loss, liability or expense;

              (4)    the Trustee does not comply with the request within 60 days
                     after receipt of the request and the offer and, if
                     requested, the provision of indemnity; and

              (5)    during such 60-day period the Holders of a majority in
                     principal amount of the then outstanding Notes do not give
                     the Trustee a direction inconsistent with the request.

       A Holder of a Note may not use this Indenture to prejudice the rights of
another Holder of a Note or to obtain a preference or priority over another
Holder of a Note.

       Section 6.07. Rights of Holders of Notes to Receive Payment.

       Notwithstanding any other provision of this Indenture, the right of any
Holder of a Note to receive payment of principal of, premium, if any, and
interest on the Note, on or after the respective due dates expressed in the Note
(including in connection with an offer to purchase), or to bring suit for the
enforcement of any such payment on or after such respective dates, shall not be
impaired or affected without the consent of such Holder.

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<PAGE>

       Section 6.08. Collection Suit by Trustee.

       If an Event of Default specified in Section 6.01(a) or (b) occurs and is
continuing, the Trustee is authorized to recover judgment in its own name and as
trustee of an express trust against the Company for the whole amount of
principal of, premium, if any, and interest remaining unpaid on the Notes and
interest on overdue principal and, to the extent lawful, interest and such
further amount as shall be sufficient to cover the costs and expenses of
collection, including the reasonable compensation, expenses, disbursements and
advances of the Trustee, its agents and counsel.

       Section 6.09. Trustee May File Proofs of Claim.

       The Trustee is authorized to file such proofs of claim and other papers
or documents as may be necessary or advisable in order to have the claims of the
Trustee (including any claim for the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel) and the
Holders of the Notes allowed in any judicial proceedings relative to the Company
(or any other obligor upon the Notes), its creditors or its property and shall
be entitled and empowered to collect, receive and distribute any money or other
property payable or deliverable on any such claims and any custodian in any such
judicial proceeding is hereby authorized by each Holder to make such payments to
the Trustee, and in the event that the Trustee shall consent to the making of
such payments directly to the Holders, to pay to the Trustee any amount due to
it for the reasonable compensation, expenses, disbursements and advances of the
Trustee, its agents and counsel, and any other amounts due the Trustee under
Section 7.07 hereof. To the extent that the payment of any such compensation,
expenses, disbursements and advances of the Trustee, its agents and counsel, and
any other amounts due the Trustee under Section 7.07 hereof out of the estate in
any such proceeding, shall be denied for any reason, payment of the same shall
be secured by a Lien on, and shall be paid out of, any and all distributions,
dividends, money, securities and other properties that the Holders may be
entitled to receive in such proceeding whether in liquidation or under any plan
of reorganization or arrangement or otherwise. Nothing herein contained shall be
deemed to authorize the Trustee to authorize or consent to or accept or adopt on
behalf of any Holder any plan of reorganization, arrangement, adjustment or
composition affecting the Notes or the rights of any Holder, or to authorize the
Trustee to vote in respect of the claim of any Holder in any such proceeding.

       Section 6.10. Priorities.

       If the Trustee collects any money pursuant to this Article, it shall pay
out the money in the following order:

       First: to the Trustee, its agents and attorneys for amounts due under
       Section 7.07 hereof, including payment of all compensation, expense and
       liabilities incurred, and all advances made, by the Trustee and the costs
       and expenses of collection;

       Second: to Holders of Notes for amounts due and unpaid on the Notes for
       principal, premium, if any, and interest, ratably, without preference or
       priority of any kind,

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<PAGE>

       according to the amounts due and payable on the Notes for principal,
       premium, if any and interest, respectively; and

       Third: to the Company or to such party as a court of competent
       jurisdiction shall direct.

       The Trustee may fix a record date and payment date for any payment to
Holders of Notes pursuant to this Section 6.10.

       Section 6.11. Undertaking for Costs.

       In any suit for the enforcement of any right or remedy under this
Indenture or in any suit against the Trustee for any action taken or omitted by
it as a Trustee, a court in its discretion may require the filing by any party
litigant in the suit of an undertaking to pay the costs of the suit, and the
court in its discretion may assess reasonable costs, including reasonable
attorneys' fees and expenses, against any party litigant in the suit, having due
regard to the merits and good faith of the claims or defenses made by the party
litigant. This Section does not apply to a suit by the Trustee, a suit by a
Holder of a Note pursuant to Section 6.07 hereof, or a suit by Holders of more
than 10% in principal amount of the then outstanding Notes.

                                   ARTICLE 7

                                    TRUSTEE

       Section 7.01. Duties of Trustee.

       (a) If an Event of Default has occurred and is continuing, the Trustee
shall exercise such of the rights and powers vested in it by this Indenture, and
use the same degree of care and skill in its exercise, as a prudent person would
exercise or use under the circumstances in the conduct of such person's own
affairs.

       (b) Except during the continuance of an Event of Default:

              (i)    the duties of the Trustee shall be determined solely by the
                     express provisions of this Indenture and the Trustee need
                     perform only those duties that are specifically set forth
                     in this Indenture and no others, and no implied covenants
                     or obligations shall be read into this Indenture against
                     the Trustee; and

              (ii)   in the absence of bad faith on its part, the Trustee may
                     conclusively rely, as to the truth of the statements and
                     the correctness of the opinions expressed therein, upon
                     certificates or opinions furnished to the Trustee and
                     conforming to the requirements of this Indenture. However,
                     the Trustee shall examine the certificates and opinions
                     required to be furnished to the Trustee hereunder to
                     determine whether or not they conform to the requirements
                     of this Indenture.

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<PAGE>

       (c) The Trustee may not be relieved from liabilities for its own
negligent action, its own negligent failure to act, or its own willful
misconduct, except that:

              (i)    this paragraph does not limit the effect of paragraph (b)
                     of this Section;

              (ii)   the Trustee shall not be liable for any error of judgment
                     made in good faith by a Responsible Officer, unless it is
                     proved that the Trustee was negligent in ascertaining the
                     pertinent facts; and

              (iii)  the Trustee shall not be liable with respect to any action
                     it takes or omits to take in good faith in accordance with
                     a direction received by it pursuant to Section 6.05 hereof.

       (d) Whether or not therein expressly so provided, every provision of this
Indenture that in any way relates to the Trustee is subject to paragraphs (a),
(b), and (c) of this Section.

       (e) No provision of this Indenture shall require the Trustee to expend or
risk its own funds or incur any liability. The Trustee shall be under no
obligation to exercise any of its rights and powers under this Indenture at the
request of any Holders, unless such Holder shall have offered to the Trustee
security and indemnity satisfactory to it against any loss, liability or
expense.

       (f) The Trustee shall not be liable for interest on any money received by
it except as the Trustee may agree in writing with the Company. Money held in
trust by the Trustee need not be segregated from other funds except to the
extent required by law.

       Section 7.02. Rights of Trustee.

       (a) The Trustee may conclusively rely upon any document (whether in its
original or facsimile form) believed by it to be genuine and to have been signed
or presented by the proper Person. The Trustee need not investigate any fact or
matter stated in the document.

       (b) Before the Trustee acts or refrains from acting, it may require an
Officers' Certificate or an Opinion of Counsel or both. The Trustee shall not be
liable for any action it takes or omits to take in good faith in reliance on
such Officers' Certificate or Opinion of Counsel. The Trustee may consult with
counsel of its own selection and the written and oral advice of such counsel or
any Opinion of Counsel shall be full and complete authorization and protection
from liability in respect of any action taken, suffered or omitted by it
hereunder in good faith and in reliance thereon.

       (c) The Trustee may act through its attorneys and agents and shall not be
responsible for the misconduct or negligence of any agent appointed with due
care.

       (d) The Trustee shall not be liable for any action it takes or omits to
take in good faith that it believes to be authorized or within the rights or
powers conferred upon it by this Indenture.

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<PAGE>

       (e) Unless otherwise specifically provided in this Indenture, any demand,
request, direction or notice from the Company shall be sufficient if signed by
an Officer of the Company.

       (f) The Trustee shall be under no obligation to exercise any of the
rights or powers vested in it by this Indenture at the request or direction of
any of the Holders unless such Holders shall have offered to the Trustee
reasonable security or indemnity against the costs, expenses and liabilities
that might be incurred by it in compliance with such request or direction.

       Section 7.03. Individual Rights of Trustee.

       The Trustee in its individual or any other capacity may become the owner
or pledgee of Notes and may otherwise deal with the Company or any Affiliate of
the Company with the same rights it would have if it were not Trustee. However,
in the event that the Trustee acquires any conflicting interest it must
eliminate such conflict within 90 days, apply to the SEC for permission to
continue as trustee or resign. Any Agent may do the same with like rights and
duties. The Trustee is also subject to Sections 7.10 and 7.11 hereof.

       Section 7.04. Trustee's Disclaimer.

       The Trustee shall not be responsible for and makes no representation as
to the validity or adequacy of this Indenture or the Notes, it shall not be
accountable for the Company's use of the proceeds from the Notes or any money
paid to the Company or upon the Company's direction under any provision of this
Indenture, it shall not be responsible for the use or application of any money
received by any Paying Agent other than the Trustee, and it shall not be
responsible for any statement or recital herein or any statement in the Notes or
any other document in connection with the sale of the Notes or pursuant to this
Indenture other than its certificate of authentication.

       Section 7.05. Notice of Defaults.

       If a Default or Event of Default occurs and is continuing and if it is
actually known to a Responsible Officer of the Trustee, the Trustee shall mail
to Holders of Notes a notice of the Default or Event of Default within 90 days
after it occurs. Except in the case of a Default or Event of Default in payment
of principal of, premium, if any, or interest on any Note, the Trustee may
withhold the notice if and so long as a committee of its Responsible Officers in
good faith determines that withholding the notice is in the interests of the
Holders of the Notes.

       Section 7.06. Reports by Trustee to Holders of the Notes.

       Within 60 days after each May 15 beginning with the May 15 following the
date of this Indenture, and for so long as Notes remain outstanding, the Trustee
shall mail to the Holders of the Notes a brief report dated as of such reporting
date that complies with TIA ss. 313(a) (but if no event described in TIA ss.
313(a) has occurred within the twelve months preceding the reporting date, no
report need be transmitted). The Trustee also shall comply with TIA ss. 313(b).
The Trustee shall also transmit by mail all reports as required by TIA ss.
313(c).

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<PAGE>

       A copy of each report at the time of its mailing to the Holders of Notes
shall be mailed to the Company and filed with the SEC and each stock exchange on
which the Notes are listed in accordance with TIA ss. 313(d). The Company shall
promptly notify the Trustee when the Notes are listed on any stock exchange or
delisted therefrom.

       Section 7.07. Compensation and Indemnity.

       The Company shall pay to the Trustee from time to time reasonable
compensation for its acceptance of this Indenture and services hereunder. The
Trustee's compensation shall not be limited by any law on compensation of a
trustee of an express trust. The Company shall reimburse the Trustee promptly
upon request for all reasonable disbursements, advances and expenses incurred or
made by it in addition to the compensation for its services. Such expenses shall
include the reasonable compensation, disbursements and expenses of the Trustee's
agents and counsel.

       The Company shall fully indemnify the Trustee against any and all losses,
liabilities, claims, damages or expenses (including legal fees and expenses)
incurred by it arising out of or in connection with the acceptance or
administration of its duties under this Indenture, including the costs and
expenses of enforcing this Indenture against the Company (including this Section
7.07) and defending itself against any claim (whether asserted by the Company or
any Holder or any other person) or liability in connection with the exercise or
performance of any of its powers or duties hereunder, except to the extent any
such loss, liability or expense is caused by its own negligence or willful
misconduct. The Trustee shall notify the Company promptly of any claim for which
it may seek indemnity. Failure by the Trustee to so notify the Company shall not
relieve the Company of its obligations hereunder. The Company shall defend the
claim and the Trustee shall cooperate in the defense. The Trustee may have
separate counsel and the Company shall pay the reasonable fees and expenses of
such counsel. The Company need not pay for any settlement made without its
consent, which consent shall not be unreasonably withheld.

       The obligations of the Company under this Section 7.07 shall survive the
satisfaction and discharge of this Indenture and the resignation or removal of
the Trustee.

       To secure the Company's payment obligations in this Section, the Trustee
shall have a Lien prior to the Notes on all money or property held or collected
by the Trustee, except that held in trust to pay principal and interest on
particular Notes. Such Lien shall survive the satisfaction and discharge of this
Indenture.

       When the Trustee incurs expenses or renders services after an Event of
Default specified in Section 6.01(g) or (h) hereof occurs, the expenses and the
compensation for the services (including the fees and expenses of its agents and
counsel) are intended to constitute expenses of administration under any
Bankruptcy Law.

       The Trustee shall comply with the provisions of TIA ss. 313(b)(2) to the
extent applicable.

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       Section 7.08. Replacement of Trustee.

       A resignation or removal of the Trustee and appointment of a successor
Trustee shall become effective only upon the successor Trustee's acceptance of
appointment as provided in this Section.

       The Trustee may resign in writing at any time and be discharged from the
trust hereby created by so notifying the Company. The Holders of a majority in
principal amount of the then outstanding Notes may remove the Trustee by so
notifying the Trustee and the Company in writing. The Company may remove the
Trustee if:

              (a)    the Trustee fails to comply with Section 7.10 hereof;

              (b)    the Trustee is adjudged a bankrupt or an insolvent or an
                     order for relief is entered with respect to the Trustee
                     under any Bankruptcy Law;

              (c)    a custodian or public officer takes charge of the Trustee
                     or its property; or

              (d)    the Trustee becomes incapable of acting.

       If the Trustee resigns or is removed or if a vacancy exists in the office
of Trustee for any reason, the Company shall promptly appoint a successor
Trustee. Within one year after the successor Trustee takes office, the Holders
of a majority in principal amount of the then outstanding Notes may appoint a
successor Trustee to replace the successor Trustee appointed by the Company.

       If a successor Trustee does not take office within 60 days after the
retiring Trustee resigns or is removed, the retiring Trustee, the Company, or
the Holders of at least 10% in principal amount of the then outstanding Notes
may petition at the expense of the Company any court of competent jurisdiction
for the appointment of a successor Trustee.

       If the Trustee, after written request by any Holder who has been a Holder
for at least six months, fails to comply with Section 7.10, such Holder may
petition any court of competent jurisdiction for the removal of the Trustee and
the appointment of a successor Trustee.

       A successor Trustee shall deliver a written acceptance of its appointment
to the retiring Trustee and to the Company. Thereupon, the resignation or
removal of the retiring Trustee shall become effective, and the successor
Trustee shall have all the rights, powers and duties of the Trustee under this
Indenture. The successor Trustee shall mail a notice of its succession to
Holders. The retiring Trustee shall promptly transfer all property held by it as
Trustee to the successor Trustee, provided all sums owing to the Trustee
hereunder have been paid and subject to the Lien provided for in Section 7.07
hereof.

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       Section 7.09. Successor Trustee by Merger, etc.

       If the Trustee consolidates, merges or converts into, or transfers all or
substantially all of its corporate trust business to, another corporation, the
successor corporation without any further act shall be the successor Trustee.

       Section 7.10. Eligibility; Disqualification.

       There shall at all times be a Trustee hereunder that is a corporation
organized and doing business under the laws of the United States of America or
of any state thereof that is authorized under such laws to exercise corporate
trustee power, that is subject to supervision or examination by federal or state
authorities and that has a combined capital and surplus of at least $75.0
million as set forth in its most recent published annual report of condition.

       This Indenture shall always have a Trustee who satisfies the requirements
of TIA ss. 310(a)(1), (2) and (5). The Trustee is subject to TIA ss. 310(b). For
purposes of TIA ss. 310(b)(1)(C)(i), the indentures relating to the Convertible
Notes are hereby specifically described.

       Section 7.11. Preferential Collection of Claims Against Company.

       The Trustee is subject to TIA ss. 311(a), excluding any creditor
relationship listed in TIA ss. 311(b). A Trustee who has resigned or been
removed shall be subject to TIA ss. 311(a) to the extent indicated therein.

       Section 7.12. Trustee's Application for Instructions from the Company.

       Any application by the Trustee for written instructions from the Company
may, at the option of the Trustee, set forth in writing any action proposed to
be taken or omitted by the Trustee under this Indenture and the date on and/or
after which such action shall be taken or such omission shall be effective. The
Trustee shall not be liable for any action taken by, or omission of, the Trustee
in accordance with a proposal included in such application on or after the date
specified in such application (which date shall not be less than three Business
Days after the date any officer of the Company actually receives such
application, unless any such officer shall have consented in writing to any
earlier date) unless prior to taking any such action (or the effective date in
the case of an omission), the Trustee shall have received written instructions
in response to such application specifying the action to be taken or omitted.

                                   ARTICLE 8

                   LEGAL DEFEASANCE AND COVENANT DEFEASANCE

       Section 8.01. Option to Effect Legal Defeasance or Covenant Defeasance.

       The Company may, at the option of its Board of Directors evidenced by a
resolution set forth in an Officers' Certificate, at any time, elect to have
either Section 8.02 or 8.03 hereof be

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applied to all outstanding Notes upon compliance with the conditions set forth
below in this Article 8.

       Section 8.02. Legal Defeasance and Discharge.

       Upon the Company's exercise under Section 8.01 hereof of the option
applicable to this Section 8.02, the Company shall, subject to the satisfaction
of the conditions set forth in Section 8.04 hereof, be deemed to have been
discharged from its obligations with respect to all outstanding Notes on the
date the conditions set forth below are satisfied (hereinafter, "Legal
Defeasance"). For this purpose, Legal Defeasance means that the Company shall be
deemed to have paid and discharged the entire Indebtedness represented by the
outstanding Notes, which shall thereafter be deemed to be "outstanding" only for
the purposes of Section 8.05 hereof and the other Sections of this Indenture
referred to in (1) and (2) below, and to have satisfied all its other
obligations under such Notes and this Indenture (and the Trustee, on demand of
and at the expense of the Company, shall execute proper instruments provided to
it acknowledging the same), except for the following provisions which shall
survive until otherwise terminated or discharged hereunder:

              (1)    the rights of Holders of outstanding Notes to receive
                     solely from the trust fund described in Section 8.04
                     hereof, and as more fully set forth in such Section,
                     payments in respect of the principal of, premium, if any,
                     and interest on such Notes when such payments are due;

              (2)    the Company's obligations with respect to such Notes under
                     Article 2 and Section 4.02 hereof;

              (3)    the rights, powers, trusts, duties and immunities of the
                     Trustee hereunder and the Company's obligations in
                     connection therewith; and

              (4)    this Article 8.

       Subject to compliance with this Article 8, the Company may exercise its
option under this Section 8.02 notwithstanding the prior exercise of its option
under Section 8.03 hereof.

       Section 8.03. Covenant Defeasance.

       Upon the Company's exercise under Section 8.01 hereof of the option
applicable to this Section 8.03, the Company shall, subject to the satisfaction
of the conditions set forth in Section 8.04 hereof, be released from its
obligations under the covenants contained in Sections 4.07, 4.08, 4.09, 4.10,
4.11, 4.12, 4.14, 4.15, 4.16 and 4.17 hereof and clause 2(d) of Section 5.01
hereof with respect to the outstanding Notes on and after the date the
conditions set forth in Section 8.04 are satisfied (hereinafter, "Covenant
Defeasance"), and the Notes shall thereafter be deemed not "outstanding" for the
purposes of any direction, waiver, consent or declaration or act of Holders (and
the consequences of any thereof) in connection with such covenants, but shall
continue to be deemed "outstanding" for all other purposes hereunder (it being
understood that such Notes shall not be deemed outstanding for accounting
purposes). For this purpose,

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Covenant Defeasance means that, with respect to the outstanding Notes, the
Company may omit to comply with and shall have no liability in respect of any
term, condition or limitation set forth in any such covenant, whether directly
or indirectly, by reason of any reference elsewhere herein to any such covenant
or by reason of any reference in any such covenant to any other provision herein
or in any other document and such omission to comply shall not constitute a
Default or an Event of Default under Section 6.01 hereof, but, except as
specified above, the remainder of this Indenture and such Notes shall be
unaffected thereby. In addition, upon the Company's exercise under Section 8.01
hereof of the option applicable to this Section 8.03 hereof, subject to the
satisfaction of the conditions set forth in Section 8.04 hereof, Sections
6.01(3) through 6.01(6) hereof shall not constitute Events of Default.

       Section 8.04. Conditions to Legal or Covenant Defeasance.

       The following shall be the conditions to the application of either
Section 8.02 or 8.03 hereof to the outstanding Notes:

       In order to exercise either Legal Defeasance or Covenant Defeasance:

              (1)    the Company must irrevocably deposit with the Trustee, in
                     trust, for the benefit of the Holders, cash in United
                     States dollars, non-callable Government Securities, or a
                     combination thereof, in such amounts as will be sufficient,
                     in the opinion of a nationally recognized firm of
                     independent public accountants, to pay the principal of,
                     premium, if any, and interest on the outstanding Notes on
                     the stated date for payment thereof or on the applicable
                     redemption date, as the case may be, and the Company shall
                     specify whether the Notes are being defeased to maturity or
                     to a particular redemption date;

              (2)    in the case of an election under Section 8.02 hereof, the
                     Company shall have delivered to the Trustee an Opinion of
                     Counsel in the United States reasonably acceptable to the
                     Trustee confirming that:

                     (a)    the Company has received from, or there has been
                            published by, the Internal Revenue Service a ruling;
                            or

                     (b)    since the date of this Indenture, there has been a
                            change in the applicable federal income tax law, in
                            either case to the effect that, and based thereon
                            such Opinion of Counsel shall confirm that, the
                            Holders of the outstanding Notes will not recognize
                            income, gain or loss for federal income tax purposes
                            as a result of such Legal Defeasance and will be
                            subject to federal income tax on the same amounts,
                            in the same manner and at the same times as would
                            have been the case if such Legal Defeasance had not
                            occurred;

              (3)    in the case of an election under Section 8.03 hereof, the
                     Company shall have delivered to the Trustee an Opinion of
                     Counsel in the United States

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<PAGE>

                     reasonably acceptable to the Trustee confirming that the
                     Holders of the outstanding Notes will not recognize income,
                     gain or loss for federal income tax purposes as a result of
                     such Covenant Defeasance and will be subject to federal
                     income tax on the same amounts, in the same manner and at
                     the same times as would have been the case if such Covenant
                     Defeasance had not occurred;

              (4)    no Default or Event of Default shall have occurred and be
                     continuing either:

                     (a)    on the date of such deposit (other than a Default or
                            Event of Default resulting from the borrowing of
                            funds to be applied to such deposit); or

                     (b)    insofar as Sections 6.01(7) or 6.01(8) hereof are
                            concerned, at any time in the period ending on the
                            91st day after the date of deposit;

              (5)    such Legal Defeasance or Covenant Defeasance shall not
                     result in a breach or violation of, or constitute a default
                     under, any material agreement or instrument (other than
                     this Indenture) to which the Company or any of its
                     Restricted Subsidiaries is a party or by which the Company
                     or any of its Restricted Subsidiaries is bound;

              (6)    the Company shall have delivered to the Trustee an Opinion
                     of Counsel to the effect that on the 91st day following the
                     deposit, the trust funds will not be subject to the effect
                     of any applicable bankruptcy, insolvency, reorganization or
                     similar laws affecting creditors' rights generally;

              (7)    the Company shall have delivered to the Trustee an
                     Officers' Certificate stating that the deposit was not made
                     by the Company with the intent of preferring the Holders
                     over any other creditors of the Company or with the intent
                     of defeating, hindering, delaying or defrauding any other
                     creditors of the Company or others; and

              (8)    the Company shall have delivered to the Trustee an
                     Officers' Certificate and an Opinion of Counsel, each
                     stating that all conditions precedent provided for or
                     relating to the Legal Defeasance or the Covenant Defeasance
                     have been complied with.

       Section 8.05. Deposited Money and Government Securities to be Held in
Trust; Other Miscellaneous Provisions.

       Subject to Section 8.06 hereof, all money and non-callable Government
Securities (including the proceeds thereof) deposited with the Trustee (or other
qualifying trustee, collectively for purposes of this Section 8.05, the
"Trustee") pursuant to Section 8.04 hereof in respect of the outstanding Notes
shall be held in trust and applied by the Trustee, in accordance

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with the provisions of such Notes and this Indenture, to the payment, either
directly or through any Paying Agent (including the Company acting as Paying
Agent) as the Trustee may determine, to the Holders of such Notes of all sums
due and to become due thereon in respect of principal, premium, if any, and
interest, but such money need not be segregated from other funds except to the
extent required by law.

       The Company shall pay and indemnify the Trustee against any tax, fee or
other charge imposed on or assessed against the cash or non-callable Government
Securities deposited pursuant to Section 8.04 hereof or the principal and
interest received in respect thereof other than any such tax, fee or other
charge which by law is for the account of the Holders of the outstanding Notes.

       Anything in this Article 8 to the contrary notwithstanding, the Trustee
shall deliver or pay to the Company from time to time upon the request of the
Company any money or non-callable Government Securities held by it as provided
in Section 8.04 hereof which, in the opinion of a nationally recognized firm of
independent public accountants expressed in a written certification thereof
delivered to the Trustee (which may be the opinion delivered under Section
8.04(a) hereof), are in excess of the amount thereof that would then be required
to be deposited to effect an equivalent Legal Defeasance or Covenant Defeasance.

       Section 8.06. Repayment to Company.

       Any money deposited with the Trustee or any Paying Agent, or then held by
the Company, in trust for the payment of the principal of, premium, if any, or
interest on any Note and remaining unclaimed for two years after such principal,
and premium, if any, or interest has become due and payable shall be paid to the
Company on its request or (if then held by the Company) shall be discharged from
such trust; and the Holder of such Note shall thereafter look only to the
Company for payment thereof, and all liability of the Trustee or such Paying
Agent with respect to such trust money, and all liability of the Company as
trustee thereof, shall thereupon cease; provided, however, that the Trustee or
such Paying Agent, before being required to make any such repayment, may at the
expense of the Company cause to be published once, in The New York Times and The
Wall Street Journal (national edition), notice that such money remains unclaimed
and that, after a date specified therein, which shall not be less than 30 days
from the date of such notification or publication, any unclaimed balance of such
money then remaining will be repaid to the Company.

       Section 8.07. Reinstatement.

       If the Trustee or Paying Agent is unable to apply any United States
dollars or non-callable Government Securities in accordance with Section 8.02 or
8.03 hereof, as the case may be, by reason of any order or judgment of any court
or governmental authority enjoining, restraining or otherwise prohibiting such
application, then the Company's obligations under this Indenture and the Notes
shall be revived and reinstated as though no deposit had occurred pursuant to
Section 8.02 or 8.03 hereof until such time as the Trustee or Paying Agent is
permitted to apply all such money in accordance with Section 8.02 or 8.03
hereof, as the case may be; provided, however, that, if the Company makes any
payment of principal of, premium, if

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<PAGE>

any, or interest on any Note following the reinstatement of its obligations, the
Company shall be subrogated to the rights of the Holders of such Notes to
receive such payment from the money held by the Trustee or Paying Agent.

                                   ARTICLE 9

                       AMENDMENT, SUPPLEMENT AND WAIVER

       Section 9.01. Without Consent of Holders of Notes.

       Notwithstanding Section 9.02 of this Indenture, the Company and the
Trustee may amend or supplement this Indenture or the Notes without the consent
of any Holder of Notes:

              (1)    to cure any ambiguity, defect or inconsistency;

              (2)    to provide for uncertificated Notes in addition to or in
                     place of certificated Notes or to alter the provisions of
                     Article 2 hereof (including the related definitions) in a
                     manner that does not materially adversely affect any
                     Holder;

              (3)    to provide for the assumption of the Company's obligations
                     to the Holders of the Notes by a successor to the Company
                     pursuant to Article 5 hereof;

              (4)    to secure the Notes or make any change that would provide
                     any additional rights or benefits to the Holders of the
                     Notes or that does not adversely affect the legal rights
                     hereunder of any Holder of Notes;

              (5)    to comply with requirements of the SEC in order to effect
                     or maintain the qualification of this Indenture under the
                     TIA; or

              (6)    to provide for Note Guarantees in accordance with Section
                     4.17 and Article 10 hereof.

       Upon the request of the Company accompanied by a resolution of its Board
of Directors authorizing the execution of any such amended or supplemental
Indenture, and upon receipt by the Trustee of the documents described in Section
7.02 hereof, the Trustee shall join with the Company in the execution of any
amended or supplemental Indenture authorized or permitted by the terms of this
Indenture and to make any further appropriate agreements and stipulations that
may be therein contained, but the Trustee shall not be obligated to enter into
such amended or supplemental Indenture that affects its own rights, duties or
immunities under this Indenture or otherwise.

       Section 9.02. With Consent of Holders of Notes.

       Except as provided below in this Section 9.02, the Company and the
Trustee may amend or supplement this Indenture (including Section 3.09, 4.10 and
4.14 hereof) and the Notes with

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<PAGE>

the consent of the Holders of at least a majority in principal amount of the
Notes then outstanding, voting as a single class, (including, without
limitation, consents obtained in connection with a tender offer or exchange
offer for, or purchase of, the Notes), and, subject to Sections 6.04 and 6.07
hereof, any existing Default or Event of Default (other than an uncured Default
or Event of Default in the payment of the principal of, premium, if any, or
interest on the Notes, except a payment default resulting from an acceleration
that has been rescinded) or compliance with any provision of this Indenture or
the Notes may be waived with the consent of the Holders of a majority in
principal amount of the then outstanding Notes, voting as a single class,
(including consents obtained in connection with a tender offer or exchange offer
for, or purchase of, the Notes). Section 2.08 hereof shall determine which Notes
are considered to be "outstanding" for purposes of this Section 9.02.

       Upon the request of the Company accompanied by a resolution of its Board
of Directors authorizing the execution of any such amended or supplemental
Indenture, and upon the filing with the Trustee of evidence satisfactory to the
Trustee of the consent of the Holders of Notes as aforesaid, and upon receipt by
the Trustee of the documents described in Section 7.02 hereof, the Trustee shall
join with the Company in the execution of such amended or supplemental Indenture
unless such amended or supplemental Indenture directly affects the Trustee's own
rights, duties or immunities under this Indenture or otherwise, in which case
the Trustee may in its discretion, but shall not be obligated to, enter into
such amended or supplemental Indenture.

       It shall not be necessary for the consent of the Holders of Notes under
this Section 9.02 to approve the particular form of any proposed amendment or
waiver, but it shall be sufficient if such consent approves the substance
thereof.

       After an amendment, supplement or waiver under this Section becomes
effective, the Company shall mail to the Holders of Notes affected thereby a
notice briefly describing the amendment, supplement or waiver. Any failure of
the Company to mail such notice, or any defect therein, shall not, however, in
any way impair or affect the validity of any such amended or supplemental
Indenture or waiver. Subject to Sections 6.04 and 6.07 hereof, the Holders of a
majority in aggregate principal amount of the Notes then outstanding, voting as
a single class, may waive compliance in a particular instance by the Company
with any provision of this Indenture or the Notes. However, without the consent
of each Holder affected, an amendment or waiver under this Section 9.02 may not
(with respect to any Notes held by a non-consenting Holder):

              (1)    reduce the principal amount of Notes whose Holders must
                     consent to an amendment, supplement or waiver;

              (2)    reduce the principal of or change the fixed maturity of any
                     Note or alter or waive any of the provisions with respect
                     to the redemption of the Notes, except as provided above
                     with respect to Sections 3.09, 4.10 and 4.14 hereof;

              (3)    reduce the rate of or change the time for payment of
                     interest, including default interest, on any Note;

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<PAGE>

              (4)    waive an uncured Default or Event of Default in the payment
                     of principal of or premium, if any, or interest on the
                     Notes (except a rescission of acceleration of the Notes by
                     the Holders of at least a majority in aggregate principal
                     amount of the then outstanding Notes and a waiver of the
                     payment default that resulted from such acceleration);

              (5)    make any Note payable in money other than that stated in
                     the Notes;

              (6)    make any change in the provisions of this Indenture
                     relating to waivers of past Defaults or the rights of
                     Holders of Notes to receive payments of principal of, or
                     premium, if any, or interest on the Notes;

              (7)    waive a redemption payment (but not any payment pursuant to
                     Sections 3.09, 4.10 or 4.14 hereof) with respect to any
                     Note;

              (8)    except as provided under Article 8 hereof or in accordance
                     with the terms of any Note Guarantee, release any Guarantor
                     from any of its obligations under its Note Guarantee or
                     make any change in a Note Guarantee that would adversely
                     affect the Holders of the Notes; or

              (9)    make any change in Section 6.04 or 6.07 hereof or in the
                     foregoing amendment and waiver provisions.

       Section 9.03. Compliance with Trust Indenture Act.

       Every amendment or supplement to this Indenture or the Notes shall be set
forth in a amended or supplemental Indenture that complies with the TIA as then
in effect.

       Section 9.04. Revocation and Effect of Consents.

       Until an amendment, supplement or waiver becomes effective, a consent to
it by a Holder of a Note is a continuing consent by the Holder of a Note and
every subsequent Holder of a Note or portion of a Note that evidences the same
debt as the consenting Holder's Note, even if notation of the consent is not
made on any Note. However, any such Holder of a Note or subsequent Holder of a
Note may revoke the consent as to its Note if the Trustee receives written
notice of revocation before the date the waiver, supplement or amendment becomes
effective. An amendment, supplement or waiver becomes effective in accordance
with its terms and thereafter binds every Holder.

       Section 9.05. Notation on or Exchange of Notes.

       The Trustee may place an appropriate notation about an amendment,
supplement or waiver on any Note thereafter authenticated. The Company in
exchange for all Notes may issue and the Trustee shall, upon receipt of an
Authentication Order, authenticate new Notes that reflect the amendment,
supplement or waiver.

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       Failure to make the appropriate notation or issue a new Note shall not
affect the validity and effect of such amendment, supplement or waiver.

       Section 9.06. Trustee to Sign Amendments, etc.

       The Trustee shall sign any amended or supplemental Indenture authorized
pursuant to this Article 9 if the amendment or supplement does not adversely
affect the rights, duties, liabilities or immunities of the Trustee. The Company
may not sign an amendment or supplemental Indenture until the Board of Directors
approves it. In executing any amended or supplemental indenture, the Trustee
shall be entitled to receive and (subject to Section 7.01 hereof) shall be fully
protected in relying upon, in addition to the documents required by Section
11.04 hereof, an Officer's Certificate and an Opinion of Counsel stating that
the execution of such amended or supplemental indenture is authorized or
permitted by this Indenture.

                                  ARTICLE 10

                                NOTE GUARANTEES

       Section 10.01. Guarantee.

       The provisions of this Article 10 shall apply only to those Subsidiaries
("Guarantors") of the Company, if any, that execute one or more supplemental
indentures to this Indenture in the form of Exhibit C to this Indenture in
compliance with the requirements of Section 4.17 of this Indenture.

       Subject to this Article 10, each of the Guarantors hereby, jointly and
severally, unconditionally guarantees to each Holder of a Note authenticated and
delivered by the Trustee and to the Trustee and its successors and assigns,
irrespective of the validity and enforceability of this Indenture, the Notes or
the Obligations of the Company hereunder or thereunder, that: (a) the principal
of and interest on the Notes will be promptly paid in full when due, whether at
maturity, by acceleration, redemption or otherwise, and interest on the overdue
principal of and interest on the Notes, if any, if lawful, and all other
Obligations of the Company to the Holders or the Trustee hereunder or thereunder
will be promptly paid in full or performed, all in accordance with the terms
hereof and thereof; and (b) in case of any extension of time of payment or
renewal of any Notes or any of such other Obligations, that same will be
promptly paid in full when due or performed in accordance with the terms of the
extension or renewal, whether at stated maturity, by acceleration or otherwise.
Failing payment when due of any amount so guaranteed or any performance so
guaranteed for whatever reason, the Guarantors shall be jointly and severally
obligated to pay the same immediately. Each Guarantor agrees that this is a
guarantee of payment and not a guarantee of collection.

       The Guarantors hereby agree that their obligations hereunder shall be
unconditional, irrespective of the validity, regularity or enforceability of the
Notes or this Indenture, the absence of any action to enforce the same, any
waiver or consent by any Holder of the Notes with respect to any provisions
hereof or thereof, the recovery of any judgment against the Company, any action
to enforce the same or any other circumstance which might otherwise constitute a
legal or

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<PAGE>

equitable discharge or defense of a guarantor. Each Guarantor hereby waives
diligence, presentment, demand of payment, filing of claims with a court in the
event of insolvency or bankruptcy of the Company, any right to require a
proceeding first against the Company, protest, notice and all demands whatsoever
and covenant that this Note Guarantee shall not be discharged except by complete
performance of the obligations contained in the Notes and this Indenture.

       If any Holder or the Trustee is required by any court or otherwise to
return to the Company, the Guarantors or any custodian, trustee, liquidator or
other similar official acting in relation to either the Company or the
Guarantors, any amount paid by either to the Trustee or such Holder, this Note
Guarantee, to the extent theretofore discharged, shall be reinstated in full
force and effect.

       Each Guarantor agrees that it shall not be entitled to any right of
subrogation in relation to the Holders in respect of any obligations guaranteed
hereby until payment in full of all obligations guaranteed hereby. Each
Guarantor further agrees that, as between the Guarantors, on the one hand, and
the Holders and the Trustee, on the other hand, (x) the maturity of the
obligations guaranteed hereby may be accelerated as provided in Article 6 hereof
for the purposes of this Note Guarantee, notwithstanding any stay, injunction or
other prohibition preventing such acceleration in respect of the obligations
guaranteed hereby, and (y) in the event of any declaration of acceleration of
such obligations as provided in Article 6 hereof, such obligations (whether or
not due and payable) shall forthwith become due and payable by the Guarantors
for the purpose of this Note Guarantee. The Guarantors shall have the right to
seek contribution from any non-paying Guarantor so long as the exercise of such
right does not impair the rights of the Holders under the Guarantee.

       Section 10.02. Limitation on Guarantor Liability.

       Each Guarantor, and by its acceptance of Notes, each Holder, hereby
confirms that it is the intention of all such parties that the Note Guarantee of
such Guarantor not constitute a fraudulent transfer or conveyance for purposes
of Bankruptcy Law, the Uniform Fraudulent Conveyance Act, the Uniform Fraudulent
Transfer Act or any similar federal or state law to the extent applicable to any
Note Guarantee. To effectuate the foregoing intention, the Trustee, the Holders
and the Guarantors hereby irrevocably agree that the obligations of such
Guarantor will not exceed an amount that, after giving effect to such maximum
amount and all other contingent and fixed liabilities of such Guarantor that are
relevant under such laws, and after giving effect to any collections from,
rights to receive contribution from or payments made by or on behalf of any
other Guarantor in respect of the obligations of such other Guarantor under this
Article 10, would result in the obligations of such Guarantor under its Note
Guarantee constituting a fraudulent transfer or conveyance.

       Section 10.03. Execution and Delivery of Note Guarantee.

       To evidence its Note Guarantee set forth in Section 10.01, each Guarantor
hereby agrees that a notation of such Note Guarantee substantially in the form
included in Exhibit C shall be endorsed by an Officer of such Guarantor on each
Note authenticated and delivered by the

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Trustee and that this Indenture shall be executed on behalf of such Guarantor by
its President or one of its Vice Presidents.

       Each Guarantor hereby agrees that its Note Guarantee set forth in Section
10.01 shall remain in full force and effect notwithstanding any failure to
endorse on each Note a notation of such Note Guarantee.

       If an Officer whose signature is on this Indenture or on the Note
Guarantee no longer holds that office at the time the Trustee authenticates the
Note on which a Note Guarantee is endorsed, the Note Guarantee shall be valid
nevertheless.

       The delivery of any Note by the Trustee, after the authentication thereof
hereunder, shall constitute due delivery of the Note Guarantee set forth in this
Indenture on behalf of the Guarantors.

       In the event that the Company creates or acquires any new Subsidiaries
subsequent to the date of this Indenture, if required by Section 4.17 hereof,
the Company shall cause such Subsidiaries to execute supplemental indentures to
this Indenture and Note Guarantees in accordance with Section 4.17 hereof and
this Article 10, to the extent applicable.

       Section 10.04. Guarantors May Consolidate, etc., on Certain Terms.

       Except as otherwise provided in Section 10.05, no Guarantor may
consolidate with or merge with or into (whether or not such Guarantor is the
surviving Person) another Person whether or not affiliated with such Guarantor
unless:

                     (a)    subject to Section 10.05 hereof, the Person formed
                            by or surviving any such consolidation or merger (if
                            other than a Guarantor or the Company)
                            unconditionally assumes all the Obligations of such
                            Guarantor, pursuant to a supplemental indenture in
                            form and substance reasonably satisfactory to the
                            Trustee, under the Notes, the Indenture and the Note
                            Guarantee on the terms set forth herein or therein;
                            and

                     (b)    immediately after giving effect to such transaction,
                            no Default or Event of Default exists.

       In case of any such consolidation or merger and upon the assumption by
the successor Person, by supplemental indenture, executed and delivered to the
Trustee and satisfactory in form to the Trustee, of the Note Guarantee endorsed
upon the Notes and the due and punctual performance of all of the covenants and
conditions of this Indenture to be performed by the Guarantor, such successor
Person shall succeed to and be substituted for the Guarantor with the same
effect as if it had been named herein as a Guarantor. Such successor Person
thereupon may cause to be signed any or all of the Note Guarantees to be
endorsed upon all of the Notes issuable hereunder which theretofore shall not
have been signed by the Company and delivered to the Trustee. All the Note
Guarantees so issued shall in all respects have the same legal rank

                                      91
<PAGE>

and benefit under this Indenture as the Note Guarantees theretofore and
thereafter issued in accordance with the terms of this Indenture as though all
of such Note Guarantees had been issued at the date of the execution hereof.

       Except as set forth in Articles 4 and 5 hereof, and notwithstanding
clauses (a) and (b) above, nothing contained in this Indenture or in any of the
Notes shall prevent any consolidation or merger of a Guarantor with or into the
Company or another Guarantor, or shall prevent any sale or conveyance of the
property of a Guarantor as an entirety or substantially as an entirety to the
Company or another Guarantor.

       Section 10.05. Releases Following Sale of Assets.

       In the event of a sale or other disposition of all or substantially all
of the assets of any Guarantor, by way of merger, consolidation or otherwise, or
a sale or other disposition of all of the Capital Stock of any Guarantor, in
each case to a Person that is not (either before or after giving effect to such
transactions) a Subsidiary of the Company, then such Guarantor (in the event of
a sale or other disposition, by way of merger, consolidation or otherwise, of
all of the Capital Stock of such Guarantor) or the Person acquiring the property
(in the event of a sale or other disposition of all or substantially all of the
assets of such Guarantor) will be released and relieved of any Obligations under
its Note Guarantee; provided, however, that the Net Proceeds of such sale or
other disposition are applied in accordance with the applicable provisions of
this Indenture, including without limitation Section 4.10 hereof. Upon delivery
by the Company to the Trustee of an Officers' Certificate and an Opinion of
Counsel to the effect that such sale or other disposition was made by the
Company in accordance with the provisions of this Indenture, including without
limitation Section 4.10 hereof, the Trustee shall execute any documents
reasonably required in order to evidence the release of any Guarantor from its
obligations under its Note Guarantee.

       Any Guarantor not released from its obligations under its Note Guarantee
shall remain liable for the full amount of principal of and interest on the
Notes and for the other obligations of any Guarantor under this Indenture as
provided in this Article 10.

                                  ARTICLE 11

                                 MISCELLANEOUS

       Section 11.01. Trust Indenture Act Controls.

       If any provision of this Indenture limits, qualifies or conflicts with
the duties imposed by TIA ss. 318(c), the imposed duties shall control.

       Section 11.02. Notices.

       Any notice or communication by the Company or the Trustee to the others
is duly given if in writing and delivered in Person or mailed by first class
mail (registered or certified, return

                                      92
<PAGE>

receipt requested), telex, telecopier or overnight air courier guaranteeing next
day delivery, to the others' address:

       If to the Company:

       American Tower Corporation
       116 Huntington Avenue
       Boston, MA 02116
       Telecopier No.:  (617) 375-7575
       Attention:  Chief Financial Officer and Secretary

       If to the Trustee:

       The Bank of New York
       101 Barclay Street, 21W
       New York, New York  10286
       Telecopier No.:  (212) 815-5915
       Attention:  Corporate Trustee Administration Department

       The Company or the Trustee, by notice to the others, may designate
       additional or different addresses for subsequent notices or
       communications.

       All notices and communications (other than those sent to Holders) shall
be deemed to have been duly given: at the time delivered by hand, if personally
delivered; five Business Days after being deposited in the mail, postage
prepaid, if mailed; when receipt acknowledged, if telecopied; and the next
Business Day after timely delivery to the courier, if sent by overnight air
courier guaranteeing next day delivery.

       Any notice or communication to a Holder shall be mailed by first class
mail, certified or registered, return receipt requested, or by overnight air
courier guaranteeing next day delivery to its address shown on the register kept
by the Registrar. Any notice or communication shall also be so mailed to any
Person described in TIA (S). 313(c), to the extent required by the TIA. Failure
to mail a notice or communication to a Holder or any defect in it shall not
affect its sufficiency with respect to other Holders.

       If a notice or communication is mailed in the manner provided above
within the time prescribed, it is duly given, whether or not the addressee
receives it.

       If the Company mails a notice or communication to Holders, it shall mail
a copy to the Trustee and each Agent at the same time.

       Section 11.03. Communication by Holders of Notes with Other Holders of
Notes.

       Holders may communicate pursuant to TIA (S). 312(b) with other Holders
with respect to their rights under this Indenture or the Notes. The Company, the
Trustee, the Registrar and anyone else shall have the protection of TIA (S).
312(c).

                                      93
<PAGE>

       Section 11.04. Certificate and Opinion as to Conditions Precedent.

       Upon any request or application by the Company to the Trustee to take any
action under this Indenture, the Company shall furnish to the Trustee:

       (a) an Officers' Certificate in form and substance reasonably
satisfactory to the Trustee (which shall include the statements set forth in
Section 11.05 hereof) stating that, in the opinion of the signers, all
conditions precedent and covenants, if any, provided for in this Indenture
relating to the proposed action have been satisfied; and

       (b) an Opinion of Counsel in form and substance reasonably satisfactory
to the Trustee (which shall include the statements set forth in Section 11.05
hereof) stating that, in the opinion of such counsel, all such conditions
precedent and covenants have been satisfied.

       Section 11.05. Statements Required in Certificate or Opinion.

       Each certificate or opinion with respect to compliance with a condition
or covenant provided for in this Indenture (other than a certificate provided
pursuant to TIA ss. 314(a)(4)) shall comply with the provisions of TIA ss.
314(e) and shall include:

       (a) a statement that the Person making such certificate or opinion has
read such covenant or condition;

       (b) a brief statement as to the nature and scope of the examination or
investigation upon which the statements or opinions contained in such
certificate or opinion are based;

       (c) a statement that, in the opinion of such Person, he, she or it has
made such examination or investigation as is necessary to enable such Person to
express an informed opinion as to whether or not such covenant or condition has
been satisfied; and

       (d) a statement as to whether or not, in the opinion of such Person, such
condition or covenant has been satisfied.

       Section 11.06. Rules by Trustee and Agents.

       The Trustee may make reasonable rules for action by or at a meeting of
Holders. The Registrar or Paying Agent may make reasonable rules and set
reasonable requirements for its functions; provided that no such rule shall
conflict with the terms of this Indenture or the TIA.

       Section 11.07. No Personal Liability of Directors, Officers, Employees
and Stockholders.

       No past, present or future director, officer, employee, incorporator,
stockholder or agent of the Company, as such, shall have any liability for any
obligations of the Company under the Notes, this Indenture or for any claim
based on, in respect of, or by reason of, such obligations or

                                      94
<PAGE>

their creation. Each Holder by accepting a Note waives and releases all such
liability. The waiver and release are part of the consideration for issuance of
the Notes.

       Section 11.08. Governing Law.

       THE INTERNAL LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO
CONSTRUE THIS INDENTURE AND THE NOTES WITHOUT GIVING EFFECT TO APPLICABLE
PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF
ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

       Section 11.09. No Adverse Interpretation of Other Agreements.

       This Indenture may not be used to interpret any other indenture, loan or
debt agreement of the Company or its Subsidiaries or of any other Person. Any
such indenture, loan or debt agreement may not be used to interpret this
Indenture.

       Section 11.10. Successors.

       All agreements of the Company in this Indenture and the Notes shall bind
its successors. All agreements of the Trustee in this Indenture shall bind its
successors.

       Section 11.11. Severability.

       In case any provision in this Indenture or in the Notes shall be invalid,
illegal or unenforceable, the validity, legality and enforceability of the
remaining provisions shall not in any way be affected or impaired thereby.

       Section 11.12. Counterpart Originals.

       The parties may sign any number of copies of this Indenture. Each signed
copy shall be an original, but all of them together represent the same
agreement.

       Section 11.13. Table of Contents, Headings, etc.

       The Table of Contents, Cross-Reference Table and Headings of the Articles
and Sections of this Indenture have been inserted for convenience of reference
only, are not to be considered a part of this Indenture and shall in no way
modify or restrict any of the terms or provisions hereof.

                         [Signatures on following page]

                                      95
<PAGE>

                                  SIGNATURES

Dated as of January 31, 2001

                                       AMERICAN TOWER CORPORATION

                                       By:
                                           -------------------------------------
                                           Name:
                                           Title:
Attest:

Name:

Title:

                                       THE BANK OF NEW YORK

                                       By:
                                           -------------------------------------
                                           Name:
                                           Title:

                                      96
<PAGE>

                                                                       EXHIBIT A

                                 [Face of Note]

[Insert the Global Note Legend, if applicable pursuant to Section 2.06(f)(i) of
the Indenture]

[If Restricted Notes, then insert - THE NOTES EVIDENCED HEREBY HAVE NOT BEEN
REGISTERED UNDER THE UNITED STATES SECURITIES ACT OF 1933 (THE "SECURITIES ACT")
AND MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT (1) TO A
PERSON WHO THE SELLER REASONABLY BELIEVES IS A QUALIFIED INSTITUTIONAL BUYER
WITHIN THE MEANING OF RULE 144A UNDER THE SECURITIES ACT PURCHASING FOR ITS OWN
ACCOUNT OR FOR THE ACCOUNT OF A QUALIFIED INSTITUTIONAL BUYER IN A TRANSACTION
MEETING THE REQUIREMENTS OF RULE 144A, (2) IN AN OFFSHORE TRANSACTION COMPLYING
WITH RULE 903 OR RULE 904 OF REGULATION S UNDER THE SECURITIES ACT OR (3)
PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT PROVIDED BY
RULE 144 THEREUNDER (IF AVAILABLE), IN EACH CASE IN ACCORDANCE WITH ALL
APPLICABLE SECURITIES LAWS OF THE STATES OF THE UNITED STATES.]

[If a Regulation S Note, then insert -- THIS NOTE HAS NOT BEEN REGISTERED UNDER
THE U.S. SECURITIES ACT OF 1933 (THE "SECURITIES ACT") AND MAY NOT BE OFFERED,
SOLD OR DELIVERED IN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT OF,
ANY U.S. PERSON, UNLESS THIS NOTE IS REGISTERED UNDER THE SECURITIES ACT OR AN
EXEMPTION FROM THE REGISTRATION REQUIREMENTS THEREOF IS AVAILABLE.]
<PAGE>

                             CUSIP/CINS ____________

                         9 3/8% Senior Notes Due 2009

No. ___                                                            $____________

                           AMERICAN TOWER CORPORATION

promises to pay to CEDE & CO. or registered assigns,
the principal sum of ____________________________________ DOLLARS on February 1,
2009.

Interest Payment Dates: February 1 and August 1

Regular Record Dates: January 15 and July 15

Dated:  ____________________

                                    AMERICAN TOWER CORPORATION

                                    By: ________________________________________
                                        Name:
                                        Title:

                                    By: ________________________________________
                                        Name:
                                        Title:

This is one of the Notes referred to in the within-mentioned Indenture:

THE BANK OF NEW YORK,
as Trustee

By: _______________________________________
    Authorized Signatory

                                      A-2
<PAGE>

                                [Back of Note]

                         9 3/8% Senior Notes Due 2009

       Capitalized terms used herein shall have the meanings assigned to them in
the Indenture referred to below unless otherwise indicated.

       1. Interest. American Tower Corporation, a Delaware corporation (the
"Company"), promises to pay interest on the principal amount of this Note at 9?%
per annum from January 31, 2001 until maturity [If Original Notes then insert --
provided, however, that if (i) on or prior to the 90th day following the Issue
Date, neither a registration statement (the "Exchange Registration Statement")
under the Securities Act, registering a note substantially identical to this
Note (except that such Note will not contain terms with respect to the
Additional Interest payments described below or transfer restrictions) pursuant
to an exchange offer (the "Exchange Offer") nor a registration statement
registering this Note for resale (a "Shelf Registration Statement") has been
filed with the Securities and Exchange Commission, (ii) on or prior to the 180th
day following the Issue Date, neither the Exchange Registration Statement nor
the Shelf Registration Statement has become or been declared effective, (iii) on
or prior to the 225th day following the Issue Date, neither the Exchange Offer
has been consummated nor the Shelf Registration Statement has been declared
effective, or (iv) either the Exchange Registration Statement or, if applicable,
the Shelf Registration Statement is declared effective but (A) thereafter ceases
to be effective or (B) ceases to be usable in connection with certain resales,
in each case (i) through (iv) upon the terms and conditions set forth in the
Registration Rights Agreement (each such event referred to in clauses (i)
through (iv), a "Registration Default"), then interest will accrue (in addition
to any stated interest on the Securities) (the "Step-Up") at a rate of 0.25% per
annum, determined daily, on the principal amount of the Notes, for the 90-day
period immediately following the occurrence of the Registration Default, which
rate shall be increased by 0.25% per annum at the beginning of each subsequent
90-day period (provided that the rate at which such additional interest accrues
shall not exceed 1.0% per annum in the aggregate) and interest shall be payable
at such increased rate until such time (the "Step-Down Date") as no Registration
Default is in effect (after which such interest rate will be restored to its
initial rate). In no event shall the Company be required to pay Step-Up interest
for more than one Registration Default at any given time. Interest accruing as a
result of the Step-Up (which shall be computed on the basis of a 365-day year)
is referred to herein as "Additional Interest." Accrued Additional Interest, if
any, shall be paid semi-annually on February 1 and August 1 in each year; and
the amount of accrued Additional Interest shall be determined on the basis of
the number of days actually elapsed. Any accrued and unpaid interest (including
Additional Interest) on this Note upon the issuance of an Exchange Note (as
defined in the Indenture) in exchange for this Note shall cease to be payable to
the Holder hereof but such accrued and unpaid interest (including Additional
Interest) shall be payable on the next Interest Payment Date for such Exchange
Note to the Holder thereof on the related Regular Record Date. The Company will
pay interest semi-annually in arrears on February 1 and August 1 of each year,
or if any such day is not a Business Day, on the next succeeding Business Day
(each, an "Interest Payment Date"). Interest on the Notes will accrue from the
most recent date to which interest has been paid or, if no interest has been
paid, from the date of issuance; provided that if there is no

                                      A-3
<PAGE>

existing Default in the payment of interest, and if this Note is authenticated
between a record date referred to on the face hereof and the next succeeding
Interest Payment Date, interest shall accrue from such next succeeding Interest
Payment Date; provided, further, that the first Interest Payment Date shall be
August 1, 2001. The Company shall pay interest (including post-petition interest
in any proceeding under any Bankruptcy Law) on overdue principal and premium [If
Original Notes then insert -- and Additional Interest], if any, from time to
time on demand at a rate that is 1% per annum in excess of the rate then in
effect; it shall pay interest (including post-petition interest in any
proceeding under any Bankruptcy Law) on overdue installments of interest
(without regard to any applicable grace periods) from time to time on demand at
the same rate to the extent lawful. Interest [If Original Notes then insert --
(other than Additional Interest)] will be computed on the basis of a 360-day
year of twelve 30-day months.

       2. Method of Payment. The Company will pay interest on the Notes (except
defaulted interest) to the Persons who are registered Holders of Notes at the
close of business on the January 15 or July 15 next preceding the Interest
Payment Date (each, a "Regular Record Date"), even if such Notes are canceled
after such record date and on or before such Interest Payment Date, except as
provided in Section 2.12 of the Indenture with respect to defaulted interest.
The Notes will be payable as to principal, premium, if any, and interest at the
office or agency of the Company maintained for such purpose within or without
the City and State of New York, or, at the option of the Company, payment of
interest may be made by check mailed to the Holders at their addresses set forth
in the register of Holders, and provided that payment by wire transfer of
immediately available funds will be required with respect to principal of,
premium, if any, and interest on, all Global Notes and all other Notes the
Holders of which shall have provided wire transfer instructions to the Company
or the Paying Agent. Such payment shall be in such coin or currency of the
United States of America as at the time of payment is legal tender for payment
of public and private debts.

       3. Paying Agent and Registrar. Initially, The Bank of New York, the
Trustee under the Indenture, will act as Paying Agent and Registrar. The Company
may change any Paying Agent or Registrar without notice to any Holder. The
Company or any of its Subsidiaries may act in any such capacity.

       4. Indenture. The Company issued the Notes under an Indenture dated as
January 31, 2001 ("Indenture") between the Company and the Trustee. The terms of
the Notes include those stated in the Indenture and those made part of the
Indenture by reference to the Trust Indenture Act of 1939, as amended (15 U.S.
Code ss.ss. 77aaa-77bbbb) (the "Trust Indenture Act"). The Notes are subject to
all such terms, and Holders are referred to the Indenture and such Act for a
statement of such terms. To the extent any provision of this Note conflicts with
the express provisions of the Indenture, the provisions of the Indenture shall
govern and be controlling. The Notes are obligations of the Company. The
Original Notes are limited to $1.0 billion in aggregate principal amount. Unless
the context otherwise requires, the Original Notes and the Exchange Notes shall
constitute one series for all purposes under the Indenture, including without
limitation, amendments, waivers, redemptions and Asset Sale Offers.

                                      A-4
<PAGE>

       5.     Optional Redemption.

              (a) Except as provided in clauses (b) and (c) of this Paragraph 5,
       the Notes will not be redeemable at the Company's option prior to
       February 1, 2005. On or after February 1, 2005, the Company may redeem
       all or a part of the Notes upon not less than 30 nor more than 60 days'
       notice, at the redemption prices (expressed as percentages of principal
       amount) set forth below plus accrued and unpaid interest, if any, on the
       Notes redeemed to the applicable redemption date (subject to the right of
       Holders of record on the relevant record date to receive interest due on
       the relevant interest payment date), if redeemed during the twelve-month
       period beginning on February 1 of the years indicated below:

              Year                                               Percentage
              ----                                               ----------

              2005...........................................    104.688%
              2006...........................................    103.125
              2007...........................................    101.562
              2008 and thereafter............................    100.000

              (b) Notwithstanding the provisions of clause (a) of this Paragraph
       5, at any time until February 1, 2004, the Company may on any one or more
       occasions redeem up to 35% of the aggregate principal amount of the Notes
       originally issued under the Indenture (excluding any Exchange Notes) at a
       redemption price equal to 109.375% of the aggregate principal amount of
       the Notes to be redeemed on the redemption date with the net cash
       proceeds of one or more Public Equity Offerings and/or Strategic Equity
       Investments provided that:

              (1) Notes (including Exchange Notes) representing at least 65% of
       the aggregate principal amount of the Notes originally issued under the
       Indenture (excluding any Exchange Notes) remain outstanding immediately
       after the occurrence of such redemption (excluding Notes held by the
       Company or any of its Subsidiaries); and

              (2) the redemption occurs within 60 days of the date of the
       closing of such Public Equity Offering or Strategic Equity Investment.

              (c) Notwithstanding the provisions of clause (a) of this Paragraph
       5, at any time prior to February 1, 2005, the Company may redeem all or a
       part of the Notes upon not less than 30 nor more than 60 days' notice at
       a redemption price equal to 100% of the principal amount thereof plus the
       Applicable Premium as of, and accrued and unpaid interest, if any, to,
       the date of redemption.

       6.     Mandatory Redemption.

       Except as set forth in paragraph 7 below, the Company shall not be
required to make mandatory redemption payments with respect to the Notes.

                                      A-5
<PAGE>

       7.     Repurchase at Option of Holder.

              (a) If there is a Change of Control, the Company shall be required
       to make an offer (a "Change of Control Offer") to repurchase all or any
       part (equal to $1,000 or an integral multiple thereof) of each Holder's
       Notes at a purchase price equal to 101% of the aggregate principal amount
       thereof plus accrued and unpaid interest thereon, if any, to the date of
       purchase (the "Change of Control Payment"). Within 30 days following any
       Change of Control, the Company shall mail a notice to each Holder setting
       forth the procedures governing the Change of Control Offer as required by
       the Indenture.

              (b) When the aggregate amount of Excess Proceeds exceeds $10.0
       million, the Company shall commence an offer to all Holders of Notes (an
       "Asset Sale Offer") pursuant to Section 3.09 of the Indenture to purchase
       the maximum principal amount of Notes that may be purchased out of the
       Excess Proceeds at an offer price in cash in an amount equal to 100% of
       the principal amount thereof, plus accrued and unpaid interest thereon,
       if any, to the date fixed for the closing of such offer, in accordance
       with the procedures set forth in the Indenture. To the extent that the
       aggregate amount of Notes tendered pursuant to an Asset Sale Offer is
       less than the Excess Proceeds, the Company (or such Restricted
       Subsidiary) may use such deficiency for any purpose not otherwise
       prohibited by the Indenture. If the aggregate principal amount of Notes
       surrendered by Holders thereof, and the holders of any other debt of the
       Company entitled to receive a comparable asset sales offer, exceeds the
       amount of Excess Proceeds, the Trustee shall select the Notes and such
       other debt to be purchased on a pro rata basis. Holders of Notes that are
       the subject of an offer to purchase will receive an Asset Sale Offer from
       the Company prior to any related purchase date and may elect to have such
       Notes purchased by completing the form entitled "Option of Holder to
       Elect Purchase" on the reverse of the Notes. [If not a Global Note,
       insert -- In the event of redemption or purchase pursuant to an Asset
       Sale Offer of this Note in part only, a new Note or Notes of like tenor
       for the unredeemed or unpurchsed portion hereof will be issued in the
       name of the Holder hereof upon the cancellation hereof.]

       8.     Notice of Redemption. Notice of redemption will be mailed at least
30 days but not more than 60 days before the redemption date to each Holder
whose Notes are to be redeemed at its registered address. Notes in denominations
larger than $1,000 may be redeemed in part but only in whole multiples of
$1,000, unless all of the Notes held by a Holder are to be redeemed. On and
after the redemption date interest ceases to accrue on Notes or portions thereof
called for redemption.

       9.     Denominations, Transfer, Exchange. The Notes are in registered
form without coupons in denominations of $1,000 and integral multiples of
$1,000. The transfer of Notes may be registered and Notes may be exchanged as
provided in the Indenture. The Registrar and the Trustee may require a Holder,
among other things, to furnish appropriate endorsements and transfer documents
and the Company may require a Holder to pay any taxes and fees required by law
or permitted by the Indenture. The Company need not exchange or register the
transfer of any Note or portion of a Note selected for redemption, except for
the unredeemed portion of any

                                      A-6
<PAGE>

Note being redeemed in part. Also, the Company need not exchange or register the
transfer of any Notes for a period of 15 days before a selection of Notes to be
redeemed or during the period between a record date and the corresponding
Interest Payment Date.

       10. Persons Deemed Owners. The registered Holder of a Note may be treated
as its owner for all purposes.

       11. Amendment, Supplement and Waiver. Subject to certain exceptions, the
Indenture or the Notes may be amended or supplemented with the consent of the
Holders of at least a majority in principal amount of the then outstanding Notes
and any existing default or compliance with any provision of the Indenture or
the Notes may be waived with the consent of the Holders of a majority in
principal amount of the then outstanding Notes. Without the consent of any
Holder of Notes, the Indenture or the Notes may be amended or supplemented to
cure any ambiguity, defect or inconsistency, to provide for uncertificated Notes
in addition to or in place of certificated Notes, to provide for the assumption
of the Company's obligations to Holders of the Notes in case of a merger or
consolidation, to make any change that would provide any additional rights or
benefits to the Holders of the Notes or that does not adversely affect the legal
rights under the Indenture of any such Holder, or to comply with the
requirements of the Securities and Exchange Commission in order to effect or
maintain the qualification of the Indenture under the Trust Indenture Act.

       12. Defaults and Remedies. Events of Default include: (i) default for 30
days in the payment when due of interest on the Notes; (ii) default in payment
when due of principal of or premium, if any, on the Notes, (iii) failure by the
Company or any of its Subsidiaries to comply with Section 3.09, 4.10, 4.14 or
5.01 of the Indenture; (iv) failure by the Company or any of its Subsidiaries
for 30 days after notice to the Company by the Trustee or the Holders of at
least 25% in principal amount of the Notes then outstanding to comply with
certain other agreements in the Indenture or the Notes; (v) default under
certain other agreements relating to Indebtedness of the Company or any
Significant Subsidiary which default (a) is caused by a failure to pay principal
of or premium, if any, or interest on such Indebtedness prior to the expiration
of the grace period provided in such Indebtedness on the date of such default or
(b) results in the acceleration of such Indebtedness prior to its express
maturity; (vi) certain final judgments for the payment of money that remain
undischarged for a period of 60 days; and (vii) certain events of bankruptcy or
insolvency with respect to the Company or any of its Significant Subsidiaries.
If any Event of Default occurs and is continuing, the Trustee or the Holders of
at least 25% in principal amount of the then outstanding Notes may declare all
the Notes to be due and payable. Notwithstanding the foregoing, in the case of
an Event of Default arising from certain events of bankruptcy or insolvency, all
outstanding Notes will become due and payable without further action or notice.
Holders may not enforce the Indenture or the Notes except as provided in the
Indenture. Subject to certain limitations, Holders of a majority in principal
amount of the then outstanding Notes may direct the Trustee in its exercise of
any trust or power. The Trustee may withhold from Holders of the Notes notice of
any continuing Default or Event of Default (except a Default or Event of Default
relating to the payment of principal or interest) if it determines that
withholding notice is in their interest. The Holders of a majority in aggregate
principal amount of the Notes then outstanding by notice to the Trustee may on
behalf of the Holders of all of the

                                      A-7
<PAGE>

Notes waive any existing Default or Event of Default and its consequences under
the Indenture except a continuing Default or Event of Default in the payment of
interest on, or the principal of, the Notes. The Company is required to deliver
to the Trustee annually a statement regarding compliance with the Indenture, and
the Company is required upon becoming aware of any Default or Event of Default,
to deliver to the Trustee a statement specifying such Default or Event of
Default.

       13. Trustee Dealings with Company. The Trustee, in its individual or any
other capacity, may make loans to, accept deposits from, and perform services
for the Company or its Affiliates, and may otherwise deal with the Company or
its Affiliates, as if it were not the Trustee.

       14. No Recourse Against Others. A director, officer, employee,
incorporator or stockholder, of the Company, as such, shall not have any
liability for any obligations of the Company under the Notes or the Indenture or
for any claim based on, in respect of, or by reason of, such obligations or
their creation. Each Holder by accepting a Note waives and releases all such
liability. The waiver and release are part of the consideration for the issuance
of the Notes.

       15. Authentication. This Note shall not be valid until authenticated by
the manual signature of the Trustee or an authenticating agent.

       16. Abbreviations. Customary abbreviations may be used in the name of a
Holder or an assignee, such as: TEN COM (= tenants in common), TEN ENT (=
tenants by the entireties), JT TEN (= joint tenants with right of survivorship
and not as tenants in common), CUST (= Custodian), and U/G/M/A (= Uniform Gifts
to Minors Act).

       17. CUSIP Numbers. Pursuant to a recommendation promulgated by the
Committee on Uniform Security Identification Procedures, the Company has caused
CUSIP numbers to be printed on the Notes and the Trustee may use CUSIP numbers
in notices of redemption as a convenience to Holders. No representation is made
as to the accuracy of such numbers either as printed on the Notes or as
contained in any notice of redemption and reliance may be placed only on the
other identification numbers placed thereon.

       The Company will furnish to any Holder upon written request and without
charge a copy of the Indenture. Requests may be made to: American Tower
Corporation, 116 Huntington Avenue, Boston, MA 02116, Attention: Chief Financial
Officer and Secretary.

                                      A-8
<PAGE>

                                Assignment Form

To assign this Note, fill in the form below:

(I) or (we) assign and transfer this Note to: __________________________________
                                              (Insert assignee's legal name)

                                   (Insert assignee's soc. sec. or tax I.D. no.)

                           (Print or type assignee's name, address and zip code)

and irrevocably appoint _________________________________________ to transfer
this Note on the books of the Company. The agent may substitute another to act
for him.

Date:_________________

                  Your Signature:______________________________

                     (Sign exactly as your name appears on
                            the face of this Note)

Signature Guarantee*:______________________

* Participant in a recognized Signature Guarantee Medallion Program (or other
signature guarantor acceptable to the Trustee).

                                      A-9
<PAGE>

                      Option of Holder to Elect Purchase

If you want to elect to have this Note purchased by the Company pursuant to
Section 4.10 or 4.14 of the Indenture, check the appropriate box below:

         [_] Section 4.10__                          [_] Section 4.14

If you want to elect to have only part of the Note purchased by the Company
pursuant to Section 4.10 or Section 4.14 of the Indenture, state the amount you
elect to have purchased:

                              $__________________

Date:________________

                  Your Signature:______________________________
                     (Sign exactly as your name appears on
                            the face of this Note)

                  Tax Identification No.:______________________

Signature Guarantee*:___________________

* Participant in a recognized Signature Guarantee Medallion Program (or other
signature guarantor acceptable to the Trustee).

                                     A-10
<PAGE>

            SCHEDULE OF EXCHANGES OF INTERESTS IN THE GLOBAL NOTE*

The following exchanges of a part of this Global Note for an interest in another
Global Note or for a Definitive Note, or exchanges of a part of another Global
Note or Definitive Note for an interest in this Global Note, have been made:

<TABLE>
<CAPTION>

                                                                           Principal Amount of
                                                                           this Global Note         Signature of
                          Amount of decrease in  Amount of decrease in      following such      authorized officer of
                           Principal Amount of    Principal Amount of          decrease              Trustee or
    Date of Exchange        this Global Note        this Global Note         (or increase)            Custodian
    ----------------        ----------------        ----------------         -------------            ---------
<S>                       <C>                    <C>                       <C>                  <C>

</TABLE>

                                     A-11

* This schedule should be included only if the Note is issued in global form.
<PAGE>

                                                                       EXHIBIT B

                        FORM OF SUPPLEMENTAL INDENTURE

                   TO BE DELIVERED BY SUBSEQUENT GUARANTORS

       Supplemental Indenture (this "Supplemental Indenture"), dated as of
________, among __________________ (the "Guaranteeing Subsidiary"), a subsidiary
of AMERICAN TOWER CORPORATION (or its permitted successor), a Delaware
corporation (the "Company"), the Company, the other Guarantors (as defined in
the Indenture referred to herein) and THE BANK OF NEW YORK, as trustee under the
Indenture referred to below (the "Trustee").

                                  WITNESSETH

       WHEREAS, the Company has heretofore executed and delivered to the Trustee
an indenture (the "Indenture"), dated as of January 31, 2001 providing for the
issuance of an aggregate principal amount of $1.0 billion of 9?% Senior Notes
due 2009 (the "Notes");

       WHEREAS, the Indenture provides that under certain circumstances the
Guaranteeing Subsidiary shall execute and deliver to the Trustee a supplemental
indenture pursuant to which the Guaranteeing Subsidiary shall unconditionally
guarantee all of the Company's Obligations under the Notes and the Indenture on
the terms and conditions set forth herein (the "Note Guarantee"); and

       WHEREAS, pursuant to Section 9.1 of the Indenture, the Trustee is
authorized to execute and deliver this Supplemental Indenture.

       NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the
Guaranteeing Subsidiary and the Trustee mutually covenant and agree for the
equal and ratable benefit of the Holders of the Notes as follows:

       1.     Capitalized Terms. Capitalized terms used herein without
definition shall have the meanings assigned to them in the Indenture.

       2.     Agreement to Guarantee. The Guaranteeing Subsidiary hereby agrees
as follows:

              (a)  Along with all Guarantors named in the Indenture, to jointly
       and severally Guarantee to each Holder of a Note authenticated and
       delivered by the Trustee and to the Trustee and its successors and
       assigns, irrespective of the validity and enforceability of the
       Indenture, the Notes or the obligations of the Company hereunder or
       thereunder, that:

              (i)  the principal of and interest on the Notes will be promptly
       paid in full when due, whether at maturity, by acceleration, redemption
       or otherwise, and interest on the overdue principal of and interest on
       the Notes, if any, if lawful, and all other obligations of the Company to
       the Holders or the Trustee hereunder or thereunder will be
<PAGE>

       promptly paid in full or performed, all in accordance with the terms
       hereof and thereof; and

              (ii) in case of any extension of time of payment or renewal of any
       Notes or any of such other obligations, that same will be promptly paid
       in full when due or performed in accordance with the terms of the
       extension or renewal, whether at stated maturity, by acceleration or
       otherwise. Failing payment when due of any amount so guaranteed or any
       performance so guaranteed for whatever reason, the Guarantors shall be
       jointly and severally obligated to pay the same immediately.

              (b) The obligations hereunder shall be unconditional, irrespective
       of the validity, regularity or enforceability of the Notes or the
       Indenture, the absence of any action to enforce the same, any waiver or
       consent by any Holder of the Notes with respect to any provisions hereof
       or thereof, the recovery of any judgment against the Company, any action
       to enforce the same or any other circumstance which might otherwise
       constitute a legal or equitable discharge or defense of a guarantor.

              (c) The following is hereby waived to the extent permitted by
       applicable law: diligence, presentment, demand of payment, filing of
       claims with a court in the event of insolvency or bankruptcy of the
       Company, any right to require a proceeding first against the Company,
       protest, notice and all demands whatsoever.

              (d) This Note Guarantee shall not be discharged except by complete
       performance of the obligations contained in the Notes and the Indenture.

              (e) If any Holder or the Trustee is required by any court or
       otherwise to return to the Company, the Guarantors, or any custodian,
       Trustee, liquidator or other similar official acting in relation to
       either the Company or the Guarantors, any amount paid by either to the
       Trustee or such Holder, this Note Guarantee, to the extent theretofore
       discharged, shall be reinstated in full force and effect.

              (f) The Guaranteeing Subsidiary shall not be entitled to any right
       of subrogation in relation to the Holders in respect of any obligations
       guaranteed hereby until payment in full of all obligations guaranteed
       hereby.

              (g) As between the Guarantors, on the one hand, and the Holders
       and the Trustee, on the other hand, (x) the maturity of the obligations
       guaranteed hereby may be accelerated as provided in Article 6 of the
       Indenture for the purposes of this Note Guarantee, notwithstanding any
       stay, injunction or other prohibition preventing such acceleration in
       respect of the obligations guaranteed hereby, and (y) in the event of any
       declaration of acceleration of such obligations as provided in Article 6
       of the Indenture, such obligations (whether or not due and payable) shall
       forthwith become due and payable by the Guarantors for the purpose of
       this Note Guarantee.

                                      B-2
<PAGE>

              (h) The Guarantors shall have the right to seek contribution from
       any non-paying Guarantor so long as the exercise of such right does not
       impair the rights of the Holders under the Guarantee.

              (i) Pursuant to Section 10.02 of the Indenture, after giving
       effect to any maximum amount and all other contingent and fixed
       liabilities of such Guarantor that are relevant under any applicable
       Bankruptcy or fraudulent conveyance laws, and after giving effect to any
       collections from, rights to receive contribution from or payments made by
       or on behalf of any other Guarantor in respect of the obligations of such
       other Guarantor under Article 10 of the Indenture would result in the
       obligations of such Guarantor under its Note Guarantee not constituting a
       fraudulent transfer or conveyance.

       3.     Execution and Delivery. Each Guaranteeing Subsidiary agrees that
the Note Guarantees shall remain in full force and effect notwithstanding any
failure to endorse on each Note a notation of such Note Guarantee.

       4.     Guaranteeing Subsidiary May Consolidate, Etc. on Certain Terms.

              (a)  The Guaranteeing Subsidiary may not consolidate with or merge
       with or into (whether or not such Guarantor is the surviving Person)
       another corporation, Person or entity whether or not affiliated with such
       Guarantor unless:

              (i)  subject to Section 10.05 of the Indenture, the Person formed
       by or surviving any such consolidation or merger (if other than a
       Guarantor or the Company) unconditionally assumes all the obligations of
       such Guarantor, pursuant to a supplemental indenture in form and
       substance reasonably satisfactory to the Trustee, under the Notes, the
       Indenture and the Note Guarantee on the terms set forth herein or
       therein; and

              (ii) immediately after giving effect to such transaction, no
       Default or Event of Default exists.

              (b)  In case of any such consolidation or merger upon the
       assumption by the successor Person, by supplemental indenture, executed
       and delivered to the Trustee and satisfactory in form to the Trustee, of
       the Note Guarantee endorsed upon the Notes and the due and punctual
       performance of all of the covenants and conditions of the Indenture to be
       performed by the Guarantor, such successor Person shall succeed to and be
       substituted for the Guarantor with the same effect as if it had been
       named herein as a Guarantor. Such successor Person thereupon may cause to
       be signed any or all of the Note Guarantees to be endorsed upon all of
       the Notes issuable hereunder which theretofore shall not have been signed
       by the Company and delivered to the Trustee. All the Note Guarantees so
       issued shall in all respects have the same legal rank and benefit under
       the Indenture as the Note Guarantees theretofore and thereafter issued in
       accordance with the terms of the Indenture as though all of such Note
       Guarantees had been issued at the date of the execution hereof.

                                      B-3
<PAGE>

              (c) Except as set forth in Articles 4 and 5 of the Indenture, and
       notwithstanding clauses (a) and (b) above, nothing contained in the
       Indenture or in any of the Notes shall prevent any consolidation or
       merger of a Guarantor with or into the Company or another Guarantor, or
       shall prevent any sale or conveyance of the property of a Guarantor as an
       entirety or substantially as an entirety to the Company or another
       Guarantor.

       5.     Releases.

              (a) In the event of a sale or other disposition of all or
       substantially all of the assets of any Guarantor, by way of merger,
       consolidation or otherwise, or a sale or other disposition of all of the
       Capital Stock of any Guarantor, in each case to a Person that is not
       (either before or after giving effect to such transactions) a Subsidiary
       of the Company, then such Guarantor (in the event of a sale or other
       disposition, by way of merger, consolidation or otherwise, of all of the
       capital stock of such Guarantor) or the Person acquiring the property (in
       the event of a sale or other disposition of all or substantially all of
       the assets of such Guarantor) will be released and relieved of any
       obligations under its Note Guarantee; provided, however, that the Net
       Proceeds of such sale or other disposition are applied in accordance with
       the applicable provisions of the Indenture, including without limitation
       Section 4.10 of the Indenture. Upon delivery by the Company to the
       Trustee of an Officers' Certificate and an Opinion of Counsel to the
       effect that such sale or other disposition was made by the Company in
       accordance with the provisions of the Indenture, including without
       limitation Section 4.10 of the Indenture, the Trustee shall execute any
       documents reasonably required in order to evidence the release of any
       Guarantor from its obligations under its Note Guarantee.

              (b) Any Guarantor not released from its obligations under its Note
       Guarantee shall remain liable for the full amount of principal of and
       interest on the Notes and for the other obligations of any Guarantor
       under the Indenture as provided in Article 10 of the Indenture.

       6.     No Recourse Against Others. No past, present or future director,
officer, employee, incorporator, stockholder or agent of the Guaranteeing
Subsidiary, as such, shall have any liability for any obligations of the Company
or any Guaranteeing Subsidiary under the Notes, any Note Guarantees, the
Indenture or this Supplemental Indenture or for any claim based on, in respect
of, or by reason of, such obligations or their creation. Each Holder of the
Notes by accepting a Note waives and releases all such liability. The waiver and
release are part of the consideration for issuance of the Notes.

       7.     NEW YORK LAW TO GOVERN. THE INTERNAL LAW OF THE STATE OF NEW YORK
SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE BUT WITHOUT
GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT
THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

                                      B-4
<PAGE>

       8.     Counterparts. The parties may sign any number of copies of this
Supplemental Indenture. Each signed copy shall be an original, but all of them
together represent the same agreement.

       9.     Effect of Headings. The Section headings herein are for
convenience only and shall not affect the construction hereof.

       10.    The Trustee. The Trustee shall not be responsible in any manner
whatsoever for or in respect of the validity or sufficiency of this Supplemental
Indenture or for or in respect of the recitals contained herein, all of which
recitals are made solely by the Guaranteeing Subsidiary and the Company.

       IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed and attested, all as of the date first above
written.

Dated:______________

                                    [Guaranteeing Subsidiary]
                                    By:_________________________________
                                       Name:
                                       Title:

                                    American Tower Corporation
                                    By:_________________________________
                                       Name:
                                       Title:

                                    [Other Guarantors]
                                    By:_________________________________
                                       Name:
                                       Title

                                    The Bank of New York
                                    as Trustee
                                    By:_________________________________
                                       Name:
                                       Title:

                                      B-5
<PAGE>

                                                                       EXHIBIT C

                         FORM OF NOTATION OF GUARANTEE

       For value received, each Guarantor (which term includes any successor
Person under the Indenture) has, jointly and severally, unconditionally
guaranteed, to the extent set forth in the Indenture and subject to the
provisions in the Indenture dated as of January 31, 2001 (the "Indenture")
between AMERICAN TOWER CORPORATION and THE BANK OF NEW YORK, as trustee (the
"Trustee"), (a) the due and punctual payment of the principal of, premium, if
any, and interest on the Notes (as defined in the Indenture), whether at
maturity, by acceleration, redemption or otherwise, the due and punctual payment
of interest on overdue principal and premium, and, to the extent permitted by
law, interest, and the due and punctual performance of all other obligations of
the Company to the Holders or the Trustee all in accordance with the terms of
the Indenture and (b) in case of any extension of time of payment or renewal of
any Notes or any of such other obligations, that the same will be promptly paid
in full when due or performed in accordance with the terms of the extension or
renewal, whether at stated maturity, by acceleration or otherwise. The
obligations of the Guarantors to the Holders of Notes and to the Trustee
pursuant to the Note Guarantee and the Indenture are expressly set forth in
Article 10 of the Indenture and reference is hereby made to the Indenture for
the precise terms of the Note Guarantee. Each Holder of a Note, by accepting the
same, agrees to and shall be bound by such provisions.

                            [Name of Guarantor(s)]

                            By:_________________________________
                               Name:
                               Title:

                                      C-1
<PAGE>

                                                                       EXHIBIT D

                       FORM OF REGULATION S CERTIFICATE

 (For transfers pursuant to Section 2.06(a), (b)(iii) and (e) of the Indenture)

The Bank of New York,
 as Trustee
101 Barclay St., 21W
New York, NY 10286
Attention: Corporate Trust Administration

                    Re:  9 3/8% Senior Notes due 2009 of
                         American Tower Corporation
                         (the "Notes")

       Reference is made to the Indenture, dated as of January 31, 2001 (the
"Indenture"), between American Tower Corporation (the "Company") and The Bank of
New York, as Trustee. Terms used herein and defined in the Indenture or in
Regulation S or Rule 144 under the U.S. Securities Act of 1933, as amended (the
"Securities Act") are used herein as so defined.

       This certificate relates to U.S. $____________ principal amount of Notes,
which are evidenced by the following certificate(s) (the "Specified Notes"):

                    CUSIP No(s). ___________________________

                    CERTIFICATE No(s). _____________________

       The person in whose name this certificate is executed below (the
"Undersigned") hereby certifies that either (i) it is the sole beneficial owner
of the Specified Notes or (ii) it is acting on behalf of all the beneficial
owners of the Specified Notes and is duly authorized by them to do so. Such
beneficial owner or owners are referred to herein collectively as the "Owner".
If the Specified Notes are represented by a Global Notes, they are held through
the Depositary or a Participant in the name of the Undersigned, as or on behalf
of the Owner. If the Specified Notes are not represented by a Global Note, they
are registered in the name of the Undersigned, as or on behalf of the Owner.

       The Owner has requested that the Specified Notes be transferred to a
person (the "Transferee") who will take delivery in the form of a Regulation S
Note. In connection with such transfer, the Owner hereby certifies that, unless
such transfer is being effected pursuant to an effective registration statement
under the Securities Act, it is being effected in accordance with Rule 904 or
Rule 144 under the Securities Act and with all applicable securities laws of the
states of the United States and other jurisdictions. Accordingly, the Owner
hereby further certifies as follows:

                                      D-1
<PAGE>

       (a)    Rule 904 Transfers. If the transfer is being effected in
accordance with Rule 904:

              (i)    the Owner is not a distributor of the Notes, an affiliate
                     of the Company or any such distributor or a person acting
                     on behalf of any of the foregoing;

              (ii)   the offer of the Specified Notes was not made to a person
                     in the United States;

              (iii)  either:

                     (1)    at the time the buy order was originated, the
                            Transferee was outside the United States or the
                            Owner and any person acting on its behalf reasonably
                            believed that the Transferee was outside the United
                            States, or

                     (2)    the transaction is being executed in, on or through
                            the facilities of the Eurobond market, as regulated
                            by the Association of International Bond Dealers, or
                            another designated offshore securities market and
                            neither the Owner nor any person acting on its
                            behalf knows that the transaction has been
                            prearranged with a buyer in the United States;

              (iv)   no directed selling efforts have been made in the United
                     States by or on behalf of the Owner or any affiliate
                     thereof;

              (v)    if the Owner is a dealer in securities or has received a
                     selling concession, fee or other remuneration in respect of
                     the Specified Notes, and the transfer is to occur during
                     the Restricted Period, then the requirements of Rule
                     904(c)(1)have been satisfied; and

              (vi)   the transaction is not part of a plan or scheme to evade
                     the registration requirements of the Securities Act.

       (b)    Rule 144 Transfers. If the transfer is being effected pursuant to
Rule 144:

              (i)    the transfer is occurring after a holding period of at
                     least one year (computed in accordance with paragraph (d)
                     of Rule 144) has elapsed since the Specified Notes were
                     last acquired from the Company or from an affiliate of the
                     Company, whichever is later, and is being effected in
                     accordance with the applicable amount, manner of sale and
                     notice requirements of Rule 144; or

              (ii)   the transfer is occurring after a holding period of at
                     least two years has elapsed since the Specified Notes were
                     last acquired from the Company or from an affiliate of the
                     Company, whichever is later, and the Owner is not,

                                      D-2
<PAGE>

                     and during the preceding three months has not been, an
                     affiliate of the Company.

       This certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the Purchasers.

       Dated:

                                 -----------------------------------------------
                                 (Print the name of the Undersigned, as such
                                 term is defined in the second paragraph of this
                                 certificate.)

                                 By:  __________________________________________
                                 Name:
                                 Title:
                                 (If the Undersigned is a corporation,
                                 partnership or fiduciary, the title of the
                                 person signing on behalf of the Undersigned
                                 must be stated.)

                                      D-3
<PAGE>

                                                                       EXHIBIT E

                      FORM OF RESTRICTED NOTES CERTIFICATE

  (For transfers pursuant to Section 2.06(a), (b)(iv) and (e) of the Indenture)

The Bank of New York,
 as Trustee
101 Barclay St., 21W
New York, NY 10286
Attention: Corporate Trust Administration

                    Re:  9 3/8% Senior Notes due 2009 of
                         American Tower Corporation
                         (the "Notes")

       Reference is made to the Indenture, dated as of January 31, 2001 (the
"Indenture"), between American Tower Corporation (the "Company") and The Bank of
New York, as Trustee. Terms used herein and defined in the Indenture or in
Regulation S or Rule 144 under the U.S. Securities Act of 1933, as amended (the
"Securities Act") are used herein as so defined.

       This certificate relates to U.S. $_____________ principal amount of
Notes, which are evidenced by the following certificate(s) (the "Specified
Notes"):

                    CUSIP No(s). ___________________________

                    CERTIFICATE No(s). _____________________

       The person in whose name this certificate is executed below (the
"Undersigned") hereby certifies that either (i) it is the sole beneficial owner
of the Specified Notes or (ii) it is acting on behalf of all the beneficial
owners of the Specified Notes and is duly authorized by them to do so. Such
beneficial owner or owners are referred to herein collectively as the "Owner".
If the Specified Notes are represented by a Global Note, they are held through
the Depositary or a Participant in the name of the Undersigned, as or on behalf
of the Owner. If the Specified Notes are not represented by a Global Note, they
are registered in the name of the Undersigned, as or on behalf of the Owner.

       The Owner has requested that the Specified Notes be transferred to a
person (the "Transferee") who will take delivery in the form of a Restricted
Note. In connection with such transfer, the Owner hereby certifies that, unless
such transfer is being effected pursuant to an effective registration statement
under the Securities Act, it is being effected in accordance with Rule 144A or
Rule 144 under the Securities Act and all applicable securities laws of the
states of the United States and other jurisdictions. Accordingly, the Owner
hereby further certifies as follows:

                                      E-1
<PAGE>

       (a)    Rule 144A Transfers. If the transfer is being effected in
accordance with Rule 144A:

              (i)    the Specified Notes are being transferred to a person that
                     the Owner and any person acting on its behalf reasonably
                     believe is a "qualified institutional buyer" within the
                     meaning of Rule 144A, acquiring for its own account or for
                     the account of a qualified institutional buyer; and

              (ii)   the Owner and any person acting on its behalf have taken
                     reasonable steps to ensure that the Transferee is aware
                     that the Owner may be relying on Rule 144A in connection
                     with the transfer.

       (b)    Rule 144 Transfers. If the transfer is being effected pursuant to
Rule 144:

              (i)    the transfer is occurring after a holding period of at
                     least one year (computed in accordance with paragraph (d)
                     of Rule 144) has elapsed since the Specified Notes were
                     last acquired from the Company or from an affiliate of the
                     Company, whichever is later, and is being effected in
                     accordance with the applicable amount, manner of sale and
                     notice requirements of Rule 144; or

              (ii)   the transfer is occurring after a holding period of at
                     least two years has elapsed since the Specified Notes were
                     last acquired from the Company or from an affiliate of the
                     Company, whichever is later, and the Owner is not, and
                     during the preceding three months has not been, an
                     affiliate of the Company.

                                      E-2
<PAGE>

       This certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the Purchasers.

       Dated:

                                 -----------------------------------------------
                                 (Print the name of the Undersigned, as such
                                 term is defined in the second paragraph of this
                                 certificate.)

                                 By:  __________________________________________
                                 Name:
                                 Title:
                                 (If the Undersigned is a corporation,
                                 partnership or fiduciary, the title of the
                                 person signing on behalf of the Undersigned
                                 must be stated.)

                                      E-3
<PAGE>

                                                                       EXHIBIT F

                     FORM OF UNRESTRICTED NOTES CERTIFICATE

 (For removal of Securities Act Legends pursuant to Section 2.06(f)(ii) of the
                                  Indenture)

The Bank of New York,
 as Trustee
101 Barclay St., 21W
New York, NY 10286
Attention:  Corporate Trust Administration

                    Re:  9 3/8% Senior Notes due 2009 of
                         American Tower Corporation
                         (the "Notes")

       Reference is made to the Indenture, dated as of January 31, 2001 (the
"Indenture"), between American Tower Corporation (the "Company") and The Bank of
New York, as Trustee. Terms used herein and defined in the Indenture or in
Regulation S or Rule 144 under the U.S. Securities Act of 1933, as amended (the
"Securities Act") are used herein as so defined.

       This certificate relates to U.S. $_____________ principal amount of
Notes, which are evidenced by the following certificate(s) (the "Specified
Notes"):

                    CUSIP No(s). ___________________________

                    CERTIFICATE No(s). _____________________

       The person in whose name this certificate is executed below (the
"Undersigned") hereby certifies that either (i) it is the sole beneficial owner
of the Specified Notes or (ii) it is acting on behalf of all the beneficial
owners of the Specified Notes and is duly authorized by them to do so. Such
beneficial owner or owners are referred to herein collectively as the "Owner".
If the Specified Notes are represented by a Global Note, they are held through
the Depositary or a Participant in the name of the Undersigned, as or on behalf
of the Owner. If the Specified Notes are not represented by a Global Note, they
are registered in the name of the Undersigned, as or on behalf of the Owner.

       The Owner has requested that the Specified Notes be exchanged for Notes
bearing no Securities Act Legend pursuant to Section 305(c) of the Indenture. In
connection with such exchange, the Owner hereby certifies that the exchange is
occurring after a holding period of at least two years (computed in accordance
with paragraph (d) of Rule 144) has elapsed since the Specified Notes were last
acquired from the Company or from an affiliate of the Company, whichever is
later, and the Owner is not, and during the preceding three months has not been,
an affiliate of the Company. The Owner also acknowledges that any future
transfers of the Specified Notes must comply with all applicable securities laws
of the states of the United States and other jurisdictions.

                                      F-1
<PAGE>

       This certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the Purchasers.

       Dated:

                                 -----------------------------------------------
                                 (Print the name of the Undersigned, as such
                                 term is defined in the second paragraph of this
                                 certificate.)

                                 By:  __________________________________________
                                 Name:
                                 Title:
                                 (If the Undersigned is a corporation,
                                 partnership or fiduciary, the title of the
                                 person signing on behalf of the Undersigned
                                 must be stated.)

                                      F-2<PAGE>

                                                                    Exhibit 4.10
                                                                    ------------

                           AMERICAN TOWER CORPORATION
                         9 3/8% Senior Notes Due 2009

                          REGISTRATION RIGHTS AGREEMENT

                                                              New York, New York
                                                                January 31, 2001

Donaldson, Lufkin & Jenrette Securities Corporation
     (an affiliate of Credit Suisse First Boston Corporation)
Salomon Smith Barney Inc.
Deutsche Banc Alex. Brown Inc.
Goldman, Sachs & Co.
Lehman Brothers Inc.
TD Securities (USA) Inc.
BNY Capital Markets, Inc.
Chase Securities Inc.
RBC Dominion Securities Corporation
Scotia Capital (USA) Inc.
Banc of America Securities LLC
BMO Nesbitt Burns Inc.
Credit Lyonnais Securities (USA) Inc.
McDonald Investments Inc.
Thomas Weisel Partners LLC

c/o Donaldson, Lufkin & Jenrette Securities Corporation
    11 Madison Avenue
    New York, New York 10010

    -and-

    Salomon Smith Barney Inc.
    388 Greenwich Street
    New York, New York 10013

Ladies and Gentlemen:

     American Tower Corporation, a corporation organized under the laws of
Delaware (the "Company"), proposes to issue and sell to certain initial
purchasers (the "Purchasers") upon the terms set forth in a purchase agreement
dated January 24, 2001 (the "Purchase Agreement"), its 9 3/8% Senior Notes Due
2009 (the "Securities"), relating to the initial placement of the Securities
(the "Initial Placement"). To induce the Purchasers to enter into the Purchase
Agreement and to satisfy a condition of your obligations thereunder, the Company

<PAGE>

agrees with you for your benefit and the benefit of the holders from time to
time of the Securities (including the Purchasers) (each a "Holder" and,
together, the "Holders"), as follows:

     1. Definitions. Capitalized terms used herein without definition shall have
        -----------
their respective meanings set forth in the Purchase Agreement. As used in this
Agreement, the following capitalized defined terms shall have the following
meanings:

     "Act" shall mean the Securities Act of 1933, as amended, and the rules and
regulations of the Commission promulgated thereunder.

     "Advice" shall have the meaning set forth in Section 4(c).

     "Affiliate" of any specified Person shall mean any other Person that,
directly or indirectly, is in control of, is controlled by, or is under common
control with, such specified Person. For purposes of this definition, control of
a Person shall mean the power, direct or indirect, to direct or cause the
direction of the management and policies of such Person whether by contract or
otherwise; and the terms "controlling" and "controlled" shall have meanings
correlative to the foregoing.

     "Broker-Dealer" shall mean any broker or dealer registered as such under
the Exchange Act.

     "Business Day" shall mean any day other than a Saturday, a Sunday or a
legal holiday or a day on which banking institutions or trust companies are
authorized or obligated by law to close in New York City.

     "Commission" shall mean the Securities and Exchange Commission.

     "Effective Time", in the case of (i) an Exchange Offer Registration
Statement, shall mean the time and date as of which the Commission declares the
Exchange Offer Registration Statement effective or as of which the Exchange
Offer Registration Statement otherwise becomes effective and (ii) a Shelf
Registration Statement shall mean the time and date as of which the Commission
declares the Shelf Registration Statement effective or as of which the Shelf
Registration Statement otherwise becomes effective.

     "Exchange Act" shall mean the Securities Exchange Act of 1934, as amended,
and the rules and regulations of the Commission promulgated thereunder.

     "Exchange Offer Registration Period" shall mean the 180 day period
following the consummation of the Registered Exchange Offer (exclusive of any
period during which any stop order shall be in effect suspending the
effectiveness of the Exchange Offer Registration Statement).

     "Exchange Offer Registration Statement" shall mean a registration statement
of the Company on an appropriate form under the Act with respect to the
Registered Exchange Offer, all amendments and supplements to such registration
statement, including post-effective amendments thereto, in each case including
the Prospectus contained therein, all exhibits thereto and all material
incorporated by reference therein.

                                       2
<PAGE>

     "Exchanging Dealer" shall mean any Holder (which may include any Purchaser)
that is a Broker-Dealer and elects to exchange for New Securities any Securities
that it acquired for its own account as a result of market-making activities or
other trading activities (but not directly from the Company or any Affiliate of
the Company) for New Securities.

     "Final Memorandum" shall mean the offering circular related to the
Securities, as amended or supplemented as of the date hereof, including any and
all exhibits thereto and any information incorporated by reference therein.

     "Holder" shall have the meaning set forth in the preamble hereto.

     "Indenture" shall mean the Indenture relating to the Securities, dated as
of January 31, 2001, between the Company and The Bank of New York, as trustee,
as the same may be amended from time to time in accordance with the terms
thereof.

     "Initial Placement" shall have the meaning set forth in the preamble
hereto.

     "Issue Date" shall mean the date of the original issuance of the
Securities.

     "Losses" shall have the meaning set forth in Section 7(d) hereof.

     "Letter Agreement" shall mean the Letter, dated January 25, 2001, from the
Company to the Purchasers relating to the Reallocation Purchases and the
Reallocation Amounts.

     "Majority Holders" shall mean, when no Registration Statement is filed
under this Agreement, the Holders of a majority of the aggregate principal
amount of Securities outstanding and shall mean, when a Registration Statement
is filed under this Agreement, the Holders of a majority of the aggregate
principal amount of Securities registered under the Registration Statement.

     "Managing Underwriters" shall mean the investment banker or investment
bankers and manager or managers that shall administer an underwritten offering.

     "New Securities" shall mean debt securities of the Company identical in all
material respects to the Securities (except that the special interest provisions
and the transfer restriction provisions shall be modified or eliminated, as
appropriate) and to be issued under the Indenture or the New Securities
Indenture.

     "New Securities Indenture" shall mean an indenture between the Company and
the New Securities Trustee, identical in all material respects to the Indenture
(except that the special interest provisions and the transfer restriction
provisions will be modified or eliminated, as appropriate).

     "New Securities Trustee" shall mean a bank or trust company reasonably
satisfactory to the Purchasers, as trustee with respect to the New Securities
under the New Securities Indenture.

                                       3
<PAGE>

     "Notice and Questionnaire" shall have the meaning set forth in Section 3(c)
hereof.

     "Prospectus" shall mean the prospectus included in any Registration
Statement (including, without limitation, a prospectus that discloses
information previously omitted from a prospectus filed as part of an effective
registration statement in reliance upon Rule 430A under the Act), as amended or
supplemented by any prospectus supplement, with respect to the terms of the
offering of any portion of the Securities or the New Securities covered by such
Registration Statement, and all amendments and supplements thereto and all
material incorporated by reference therein.

     "Purchase Agreement" shall have the meaning set forth in the preamble
hereto.

     "Purchaser" shall have the meaning set forth in the preamble hereto.

     "Registered Exchange Offer" shall mean the proposed offer of the Company to
issue and deliver to the Holders of the Securities that are not prohibited by
any law or policy of the Commission from participating in such offer, in
exchange for the Securities, a like aggregate principal amount of the New
Securities.

     "Registration Default" shall have the meaning set forth in Section 6(a)
hereof.

     "Registration Statement" shall mean any Exchange Offer Registration
Statement or Shelf Registration Statement that covers any of the Securities or
the New Securities pursuant to the provisions of this Agreement, any amendments
and supplements to such registration statement, including post-effective
amendments (in each case including the Prospectus contained therein), all
exhibits thereto and all material incorporated by reference therein.

     "Securities" shall have the meaning set forth in the preamble hereto.

     "Shelf Registration" shall mean a registration effected pursuant to Section
3 hereof.

     "Shelf Registration Period" has the meaning set forth in Section 3(b)
hereof.

     "Shelf Registration Statement" shall mean a "shelf" registration statement
of the Company pursuant to the provisions of Section 3 hereof which covers some
or all of the Securities or New Securities, as applicable, on an appropriate
form under Rule 415 under the Act, or any similar rule that may be adopted by
the Commission, amendments and supplements to such registration statement,
including post-effective amendments, in each case including the Prospectus
contained therein, all exhibits thereto and all material incorporated by
reference therein.

     "Special Interest" shall have the meaning set forth in Section 6(a) hereof.

     "Special Interest Rate" shall have the meaning set forth in Section 6(a)
hereof.

                                       4
<PAGE>

     "Transfer Restricted Securities" shall mean each Security and New Security
until, (i) in the case of any Security exchanged by a person other than a
Broker-Dealer for a freely transferable New Security in the Registered Exchange
Offer, the date on which such Security is exchanged, (ii) in the case of any New
Security held by a Broker-Dealer, following the exchange by such Broker-Dealer
in the Registered Exchange Offer of a Security for such New Security, the date
on which such New Security is sold to a purchaser who receives from such
Broker-Dealer on or prior to the date of such sale a copy of the prospectus
contained in the Exchange Offer Registration Statement, (iii) in the case of any
Security or New Security that has been effectively registered under the Act and
disposed of in accordance with the Shelf Registration Statement, the date of
such disposition, or (iv) in the case of any Security or New Security that is
distributed to the public pursuant to Rule 144 under the Act or is saleable
pursuant to Rule 144(k) under the Act, the date on which such Security or New
Security is distributed or is saleable, as the case may be.

     "Trustee" shall mean the trustee with respect to the Securities under the
Indenture.

     "underwriter" shall mean any underwriter of Securities in connection with
an offering thereof under a Shelf Registration Statement.

     2. Registered Exchange Offer. The Company shall prepare and, not later than
        -------------------------
90 days following the Issue Date (or if such 90th day is not a Business Day, the
next succeeding Business Day), shall file with the Commission the Exchange Offer
Registration Statement with respect to the Registered Exchange Offer. The
Company shall use its reasonable best efforts to cause the Exchange Offer
Registration Statement to become effective under the Act within 180 days of the
Issue Date (or if such 180th day is not a Business Day, the next succeeding
Business Day).

     (a)  Upon the effectiveness of the Exchange Offer Registration Statement,
the Company shall promptly commence the Registered Exchange Offer, it being the
objective of such Registered Exchange Offer to enable each Holder electing to
exchange Securities for New Securities (assuming that such Holder is not an
Affiliate of the Company, acquires the New Securities in the ordinary course of
such Holder's business, has no arrangements with any Person to participate in
the distribution of the New Securities and is not prohibited by any law or
policy of the Commission from participating in the Registered Exchange Offer) to
trade such New Securities from and after their receipt without any limitations
or restrictions under the Act and without material restrictions under the
securities laws of a substantial proportion of the several states of the United
States.

     (b)  In connection with the Registered Exchange Offer, the Company shall:

          (i)   mail to each Holder a copy of the Prospectus forming part of the
     Exchange Offer Registration Statement, together with an appropriate letter
     of transmittal and related documents;

          (ii)  keep the Registered Exchange Offer open for not less than 30
     Business Days and not more than 45 Business Days after the date notice
     thereof is mailed to the Holders (or, in each case, longer if required by
     applicable law);

                                       5
<PAGE>

          (iii) use its reasonable best efforts to keep the Exchange Offer
     Registration Statement continuously effective under the Act, supplemented
     and amended as required, under the Act to ensure that it is available for
     sales of New Securities by Exchanging Dealers during the Exchange Offer
     Registration Period;

          (iv)  utilize the services of a depositary for the Registered Exchange
     Offer with an address in the Borough of Manhattan in New York City, which
     may be the Trustee, the New Securities Trustee or an Affiliate of either of
     them;

          (v)   permit Holders to withdraw tendered Securities at any time prior
     to the close of business, New York time, on the last Business Day on which
     the Registered Exchange Offer is open;

          (vi)  prior to effectiveness of the Exchange Offer Registration
     Statement, provide a supplemental letter to the Commission (A) stating that
     the Company is conducting the Registered Exchange Offer in reliance on the
     position of the Commission in Exxon Capital Holdings Corporation (pub.
                                   ----------------------------------
     avail. May 13, 1988), Morgan Stanley and Co., Inc. (pub. avail. June 5,
                           ----------------------------
     1991) and Shearman & Sterling (pub. avail. July 2, 1993); and (B) including
               -------------------
     a representation that the Company has not entered into any arrangement or
     understanding with any Person to distribute the New Securities to be
     received in the Registered Exchange Offer and that, to the best of the
     Company's information and belief, each Holder participating in the
     Registered Exchange Offer is acquiring the New Securities in the ordinary
     course of business and has no arrangement or understanding with any Person
     to participate in the distribution of the New Securities; and

          (vii) comply in all material respects with all applicable laws.

     (c)  As soon as practicable after the close of the Registered Exchange
Offer, the Company shall:

          (i)   accept for exchange all Securities tendered and not validly
     withdrawn pursuant to the Registered Exchange Offer;

          (ii)  deliver to the Trustee for cancellation in accordance with
     Section 4(s) all Securities so accepted for exchange; and

          (iii) cause the New Securities Trustee promptly to authenticate and
     deliver to each Holder of Securities a principal amount of New Securities
     equal to the principal amount of the Securities of such Holder so accepted
     for exchange.

     (d)  Each Holder hereby acknowledges and agrees that any Broker-Dealer and
any such Holder using the Registered Exchange Offer to participate in a
distribution of the New Securities (x) could not under Commission policy as in
effect on the date of this Agreement rely on the position of the Commission in
Morgan Stanley and Co., Inc. (pub. avail. June 5, 1991) and Exxon Capital
----------------------------                                -------------
Holdings Corporation (pub. avail. May 13, 1988) and Shearman & Sterling (July 2,
--------------------
1993) and similar no-action letters; and (y) must comply with the registration
and prospectus delivery requirements of the Act in connection with any secondary
resale transaction

                                       6
<PAGE>

which must be covered by an effective registration statement containing the
selling security holder information required by Item 507 or 508, as applicable,
of Regulation S-K under the Act if the resales are of New Securities obtained by
such Holder in exchange for Securities acquired by such Holder directly from the
Company or one of its Affiliates. Accordingly, as a condition to its
participation in the Registered Exchange offer, each Holder participating in the
Registered Exchange Offer shall be required to represent to the Company in the
Letter of Transmittal in the Registered Exchange Offer or by other means that,
at the time of the consummation of the Registered Exchange Offer:

          (i)   any New Securities received by such Holder will be acquired in
     the ordinary course of business;

          (ii)  such Holder will have no arrangement or understanding with any
     Person to participate in the distribution of the Securities or the New
     Securities within the meaning of the Act; and

          (iii) such Holder is not an Affiliate of the Company.

     (e)  If any Purchaser determines that it is not eligible to participate in
the Registered Exchange Offer with respect to the exchange of Securities
constituting any portion of an unsold allotment, at the request of such
Purchaser, the Company shall issue and deliver to such Purchaser or the Person
purchasing New Securities registered under a Shelf Registration Statement as
contemplated by Section 3 hereof from such Purchaser, in exchange for such
Securities, a like principal amount of New Securities. The Company shall use its
best efforts to cause the CUSIP Service Bureau to issue the same CUSIP number
for such New Securities as for New Securities issued pursuant to the Registered
Exchange Offer.

     3. Shelf Registration. If (i) due to any change in law or applicable
        ------------------
interpretations thereof by the Commission's staff, the Company determines upon
advice of its outside counsel that it is not permitted to effect the Registered
Exchange Offer as contemplated by Section 2 hereof, or (ii) for any other reason
the Registered Exchange Offer is not consummated within 225 days of the Issue
Date (or, if such 225th day is not a Business Day, the next succeeding Business
Day) or the Exchange Offer Registration Statement is not declared effective
within 180 days of the Issue Date (or if such 180th day is not a Business Day,
the next succeeding Business Day); (iii) any Purchaser so requests with respect
to Securities that are not eligible to be exchanged for New Securities in the
Registered Exchange Offer and that are held by it following consummation of the
Registered Exchange Offer; (iv) any Holder (other than a Purchaser) is not
eligible to participate in the Registered Exchange Offer or does not receive
freely tradeable New Securities in the Registered Exchange Offer other than by
reason of such Holder being an Affiliate of the Company; or (v) in the case of
any Purchaser that participates in the Registered Exchange Offer or acquires New
Securities pursuant to Section 2(f) hereof, such Purchaser does not receive
freely tradeable New Securities in exchange for Securities constituting any
portion of an unsold allotment (it being understood that (x) the requirement
that a Purchaser deliver a Prospectus containing the information required by
Item 507 or 508 of Regulation S-K under the Act in connection with sales of New
Securities acquired in exchange for such Securities shall result in such New
Securities being not "freely tradeable"; and (y) the requirement that an
Exchanging Dealer deliver a Prospectus in connection with sales of New
Securities acquired in

                                       7
<PAGE>

the Registered Exchange Offer in exchange for Securities acquired as a result of
market-making activities or other trading activities shall not result in such
New Securities being not "freely tradeable"), the Company shall effect a Shelf
Registration Statement in accordance with subsection (b) below.

     (a) (i) The Company shall as promptly as practicable (but in no event more
than 90 days after so required or requested pursuant to this Section 3 (or, if
such 90th day is not a Business Day, the next succeeding Business Day)), file
with the Commission and thereafter (but in no event more than 180 days after the
date the Company was required or requested to make such filing pursuant to this
Section 3 (or, if such 180th day is not a Business Day, the next succeeding
Business Day)) use its reasonable best efforts to cause to be declared effective
under the Act a Shelf Registration Statement relating to the offer and sale of
the Securities or the New Securities, as applicable, by the Holders thereof from
time to time in accordance with the methods of distribution elected by such
Holders and set forth in such Shelf Registration Statement; provided, however,
                                                            --------  -------
that no Holder (other than a Purchaser) shall be entitled to have the Securities
held by it covered by such Shelf Registration Statement unless such Holder
agrees in writing to be bound by all of the provisions of this Agreement
applicable to such Holder; and provided further, that with respect to New
                               --------
Securities received by a Purchaser in exchange for Securities constituting any
portion of an unsold allotment, the Company may, if permitted by current
interpretations by the Commission's staff, file a post-effective amendment to
the Exchange Offer Registration Statement containing the information required by
Item 507 or 508 of Regulation S-K, as applicable, in satisfaction of its
obligations under this subsection with respect thereto, and any such Exchange
Offer Registration Statement, as so amended, shall be referred to herein as, and
governed by the provisions herein applicable to, a Shelf Registration Statement.
Notwithstanding anything in this Section 3, Special Interest shall accrue only
in accordance with the provisions of Section 6 hereof.

     (ii) The Company shall use its best efforts to keep the Shelf Registration
Statement continuously effective, supplemented and amended as required by the
Act, in order to permit the Prospectus forming part thereof to be usable by
Holders from the date the Shelf Registration Statement is declared effective by
the Commission until the earlier of: (i) such date as all the Securities covered
by the Shelf Registration Statement have been sold, or (ii) the date on which
all of the Securities held by persons that are not Affiliates of the Company may
be resold without registration pursuant to Rule 144(k) under the Act (such
period being called the "Shelf Registration Period"). The Company shall be
deemed not to have used its best efforts to keep the Shelf Registration
Statement effective during the requisite period if it voluntarily takes any
action that would result in Holders of Securities covered thereby not being able
to offer and sell such Securities during that period, unless (A) such action is
required by applicable law; or (B) such action is taken by the Company in good
faith and for valid business reasons (not including avoidance of the Company's
obligations hereunder), including the acquisition or divestiture of assets, so
long as the Company promptly thereafter complies with the requirements of
Section 4(k) hereof, if applicable.

     (b) Not less than 30 calendar days prior to the Effective Time of any Shelf
Registration Statement required under this Agreement, the Company shall mail the
Notice and Questionnaire (the "Notice and Questionnaire") attached as Annex E
hereto to the Holders of Transfer Restricted Securities; no Holder shall be
entitled to be named as a selling securityholder

                                       8
<PAGE>

in the Shelf Registration Statement as of the Effective Time, and no Holder
shall be entitled to use the prospectus forming a part thereof for resales of
Securities at any time, unless such Holder has returned a completed and signed
Notice and Questionnaire to the Company by the deadline for response set forth
therein; provided, however, that holders of Transfer Restricted Securities shall
have at least 28 calendar days from the date on which the Notice and
Questionnaire is first mailed to such Holders to return a completed and signed
Notice and Questionnaire to the Company.

     (c) After the Effective Time of any Shelf Registration Statement required
to be filed under this Agreement, Holders of Transfer Restricted Securities who
did not timely return a Notice and Questionnaire to the Company may return a
Notice and Questionnaire at any time and may request to be included in such
Shelf Registration Statement. If:

          (i)   the Company can include such Holder with respect to its Transfer
     Restricted Securities by means of a prospectus supplement filed pursuant to
     Rule 424(b) of the Act or by means a registration statement filed pursuant
     to Rule 462(b) of the Act, then the Company shall file such Rule 424(b)
     supplement or Rule 462(b) registration statement with the Commission within
     10 Business Days of its receipt of the Notice and Questionnaire;

          (ii)  the Company, in the opinion of its counsel, cannot include such
     Holder with respect to its Transfer Restricted Securities by means of a
     prospectus supplement to the prospectus contained as part of such effective
     Shelf Registration Statement or by means a related registration statement
     filed pursuant to Rule 462(b) of the Act, the Company shall promptly take
     any action reasonably necessary to enable such a Holder to use a
     registration statement for resale of Transfer Restricted Securities,
     including, without limitation, any action necessary to identify such
     Holders or selling securityholder in a new Shelf Registration Statement
     which the Company shall promptly file and cause to be declared effective to
     cover the resale of the Transfer Restricted Securities that are the subject
     of such request.

          (d)   In the event of a Shelf Registration Statement, in addition to
the information required to be provided in the Notice and Questionnaire, the
Company may require Holders to furnish to the Company additional information
regarding such Holder and such Holder's intended method of distribution of
Securities as may be required in order to comply with the Securities Act. Each
Holder agrees to notify the Company as promptly as practicable of any inaccuracy
or change in information previously furnished by such Holder to the Company or
of the occurrence of any event in either case as a result of which any
prospectus relating to the Shelf Registration Statement contains or would
contain an untrue statement of a material fact regarding such Holder or such
Holder's intended method of disposition of such Securities or omits to state any
material fact regarding such Holder or such Holder's intended method of
disposition of such Securities required to be stated therein or necessary to
make the statements therein not misleading in light of the circumstances then
existing, and promptly to furnish to the Company any additional information or
required so that such prospectus shall not contain, with respect to such Holder
or the disposition of such Securities, an untrue statement of a material fact or
omit to state a material fact required to be stated therein or necessary to make
the statements therein not misleading in light of the circumstances then
existing.

                                       9
<PAGE>

     4. Additional Registration Procedures. In connection with any Shelf
        ----------------------------------
Registration Statement and, to the extent applicable, any Exchange Offer
Registration Statement, the following provisions shall apply.

     (a)  The Company shall:

          (i)   furnish to you, not less than five Business Days prior to the
     filing thereof with the Commission, a copy of any Exchange Offer
     Registration Statement and any Shelf Registration Statement, and each
     amendment thereof and each amendment or supplement, if any, to the
     Prospectus included therein (including all documents incorporated by
     reference therein after the initial filing) and shall use its reasonable
     best efforts to reflect in each such document, when so filed with the
     Commission, such comments as you reasonably propose;

          (ii)  include the information set forth in Annex A hereto on the
     facing page of the Exchange Offer Registration Statement, in Annex B hereto
     in the forepart of the Exchange Offer Registration Statement in a section
     setting forth details of the Exchange Offer, in Annex C hereto in the
     underwriting or plan of distribution section of the Prospectus contained in
     the Exchange Offer Registration Statement, and in Annex D hereto in the
     letter of transmittal delivered pursuant to the Registered Exchange Offer;

          (iii) if requested by a Purchaser, include the information required by
     Item 507 or 508 of Regulation S-K, as applicable, in the Prospectus
     contained in the Exchange Offer Registration Statement; and

          (iv)  in the case of a Shelf Registration Statement, include the names
     of the Holders that propose to sell Securities pursuant to the Shelf
     Registration Statement as selling security holders.

     (b)  The Company shall ensure that:

          (i)   any Registration Statement and any amendment thereto and any
     Prospectus forming part thereof and any amendment or supplement thereto
     complies in all material respects with the Act and the rules and
     regulations thereunder; and

          (ii)  any Registration Statement and any amendment thereto does not,
     when it becomes effective, contain an untrue statement of a material fact
     or omit to state a material fact required to be stated therein or necessary
     to make the statements therein not misleading.

     (c)  The Company shall advise you, the Holders of Securities covered by any
Shelf Registration Statement and any Exchanging Dealer under any Exchange Offer
Registration Statement that has provided in writing to the Company a telephone
or facsimile number and address for notices, and, if requested by you or any
such Holder or Exchanging Dealer, shall confirm such advice in writing (which
notice pursuant to clauses (ii)-(v) hereof shall be accompanied by an
instruction to suspend the use of the Prospectus until the Company shall have
remedied the basis for such suspension):

                                      10
<PAGE>

          (i)   when a Registration Statement and any amendment thereto has been
     filed with the Commission and when the Registration Statement or any
     post-effective amendment thereto has become effective;

          (ii)  of any request by the Commission for any amendment or supplement
     to the Registration Statement or the Prospectus or for additional
     information;

          (iii) of the issuance by the Commission of any stop order suspending
     the effectiveness of the Registration Statement or the initiation of any
     proceedings for that purpose;

          (iv)  of the receipt by the Company of any notification with respect
     to the suspension of the qualification of the securities included therein
     for sale in any jurisdiction or the initiation of any proceeding for such
     purpose;

          (v)   of the happening of any event that requires any change in the
     Registration Statement or the Prospectus so that, as of such date, the
     statements therein are not misleading and do not omit to state a material
     fact required to be stated therein or necessary to make the statements
     therein (in the case of the Prospectus, in the light of the circumstances
     under which they were made) not misleading; and

          (vi)  each Holder of Securities agrees by acquisition of such
     Securities that, upon actual receipt of any notice from the Company of the
     happening of any event of the kind described in Section 4(c)(ii), (iii),
     (iv), and (v) hereof, such Holder will forthwith discontinue any and all
     dispositions of such Securities by means of the Registration Statement or
     Prospectus until such Holder's receipt of the copies of the supplemented or
     amended Prospectus contemplated by Section 4(b), or until it is advised in
     writing (the "Advice") by the Company that the use of the applicable
     Prospectus may be resumed, and has received copies of any amendments or
     supplements thereto provided, however, that this paragraph shall not
     prohibit any Holder from engaging in dispositions of the Securities through
     means other than pursuant to the Registration Statement or Prospectus, as
     long as such dispositions comply with applicable laws.

     (d)  The Company shall use its best efforts to obtain the withdrawal of any
order suspending the effectiveness of any Registration Statement or the
qualification of the securities therein for sale in any jurisdiction at the
earliest possible time.

     (e)  The Company shall furnish to each Holder of Securities covered by any
Shelf Registration Statement, without charge, at least one copy of such Shelf
Registration Statement and any post-effective amendment thereto, including all
material incorporated therein by reference, and, if the Holder so requests in
writing, all exhibits thereto (including exhibits incorporated by reference
therein).

     (f)  The Company shall, during the Shelf Registration Period, deliver to
each Holder of Securities covered by any Shelf Registration Statement, without
charge, as many copies of the Prospectus (including each preliminary Prospectus)
included in such Shelf Registration Statement and any amendment or supplement
thereto as such Holder may reasonably request. The Company consents to the use
of the Prospectus or any amendment or

                                      11
<PAGE>

supplement thereto by each of the selling Holders of securities in connection
with the offering and sale of the securities covered by the Prospectus, or any
amendment or supplement thereto, included in the Shelf Registration Statement.

     (g) The Company shall furnish to each Exchanging Dealer which so requests,
without charge, at least one copy of the Exchange Offer Registration Statement
and any post-effective amendment thereto, including all material incorporated by
reference therein, and, if the Exchanging Dealer so requests in writing, all
exhibits thereto (including exhibits incorporated by reference therein).

     (h) The Company shall promptly deliver to each Purchaser, each Exchanging
Dealer and each other Person required to deliver a Prospectus during the
Exchange Offer Registration Period, without charge, as many copies of the
Prospectus included in such Exchange Offer Registration Statement and any
amendment or supplement thereto as any such Person may reasonably request. The
Company consents to the use of the Prospectus or any amendment or supplement
thereto by any Purchaser, any Exchanging Dealer and any such other Person that
may be required to deliver a Prospectus following the Registered Exchange Offer
in connection with the offering and sale of the New Securities covered by the
Prospectus, or any amendment or supplement thereto, included in the Exchange
Offer Registration Statement.

     (i) Prior to the Registered Exchange Offer or any other offering of
Securities pursuant to any Registration Statement, the Company shall arrange, if
necessary, for the qualification of the Securities or the New Securities for
sale under the laws of such jurisdictions as any Holder shall reasonably request
and will maintain such qualification in effect so long as required; provided
that in no event shall the Company be obligated to qualify to do business in any
jurisdiction where it is not then so qualified or to take any action that would
subject it to service of process in suits, other than those arising out of the
Initial Placement, the Registered Exchange Offer or any offering pursuant to a
Shelf Registration Statement, in any such jurisdiction where it is not then so
subject or otherwise subject itself to taxation in any such jurisdiction.

     (j) The Company shall cooperate with the Holders of Securities to
facilitate the timely preparation and delivery of certificates representing New
Securities or Securities to be issued or sold pursuant to any Registration
Statement free of any restrictive legends and in such denominations and
registered in such names as Holders may request.

     (k) Upon the occurrence of any event contemplated by subsections (c)(ii)
through (v) above, the Company shall promptly prepare a post-effective amendment
to the applicable Registration Statement or an amendment or supplement to the
related Prospectus or file any other required document so that, as thereafter
delivered to Purchasers of the securities included therein, the Prospectus will
not include an untrue statement of a material fact or omit to state any material
fact necessary to make the statements therein, in the light of the circumstances
under which they were made, not misleading; provided, however, that the Company
                                            --------  -------
may delay preparing, filing and distributing any such supplements or amendments
(and continue the suspension of the use of the prospectus) if the Company
determines in good faith that such supplement or amendment would, in the
reasonable judgment of the Company, (i) interfere with or affect the negotiation
or completion of a transaction that is being contemplated by the

                                      12
<PAGE>

Company (whether or not a final decision has been made to undertake such
transaction) or (ii) involve initial or continuing disclosure obligations that
are not in the best interests of the Company's shareholders at such time;
provided, further, that neither such delay nor such suspension with respect to
--------  -------
all matters in clause (i) or (ii) shall extend for a period of more than 30 days
in any three-month period or more than 90 days for all such periods in any
twelve-month period and shall not affect the Company's obligations to pay
Special Interest as contemplated by Section 6 hereof.

     (l) In such circumstances, the period of effectiveness of the Exchange
Offer Registration Statement provided for in Section 2 and the Shelf
Registration Statement provided for in Section 3(b) shall each be extended by
the number of days from and including the date of the giving of a notice of
suspension pursuant to Section 4(c) to and including the date when the
Purchasers, the Holders of the Securities and any known Exchanging Dealer shall
have received such amended or supplemented Prospectus pursuant to this Section.

     (m) Not later than the effective date of any Registration Statement, the
Company shall provide CUSIP numbers for the Securities or the New Securities, as
the case may be, registered under such Registration Statement and provide the
Trustee with printed certificates for such Securities or New Securities, in a
form eligible for deposit with The Depository Trust Company.

     (n) The Company shall comply with all applicable rules and regulations of
the Commission and shall make generally available to its security holders no
later than 45 days after the end of any 12-month period (or 90 days after the
end of any 12-month period if such period is a fiscal year), an earnings
statement satisfying the provisions of Section 11(a) of the Act and Rule 158
thereunder (or any similar rule under the Act) for a period of at least 12
months beginning on the first day of the first fiscal quarter after the
effective date of the applicable Registration Statement.

     (o) The Company shall cause the Indenture or the New Securities Indenture,
as the case may be, to be qualified under the Trust Indenture Act in a timely
manner.

     (p) The Company may require each Holder of securities to be sold pursuant
to any Shelf Registration Statement to furnish to the Company such information
regarding the Holder and the distribution of such securities as the Company may
from time to time reasonably require for inclusion in such Registration
Statement. The Company may exclude from such Shelf Registration Statement the
Securities of any Holder that fails to furnish such information within a
reasonable time after receiving such request.

     (q) In the case of any Shelf Registration Statement, the Company shall
enter into such agreement and take all other appropriate actions (including if
requested an underwriting agreement in customary form) in order to expedite or
facilitate the registration or the disposition of the Securities, and in
connection therewith, if an underwriting agreement is entered into, cause the
same to contain indemnification provisions and procedures no less favorable than
those set forth in Section 7 (or such other provisions and procedures acceptable
to the Majority Holders and the Managing Underwriters, if any, with respect to
all parties to be indemnified pursuant to Section 7).

                                      13
<PAGE>

     (r)  In the case of any Shelf Registration Statement, the Company shall:

          (i)   make reasonably available for inspection by the Holders of
     Securities to be registered thereunder, any underwriter participating in
     any disposition pursuant to such Registration Statement, and any attorney,
     accountant or other agent retained by the Holders or any such underwriter
     all relevant and reasonably requested financial and other records,
     pertinent corporate documents and properties of the Company and its
     subsidiaries;

          (ii)  cause the Company's officers, directors and employees to supply
     all relevant information reasonably requested by the Holders or any such
     underwriter, attorney, accountant or agent in connection with any such
     Registration Statement as is customary for similar due diligence
     examinations; provided, however, that any information that is designated in
                   --------  -------
     writing by the Company, in good faith, as confidential at the time of
     delivery of such information shall be kept confidential by the Holders or
     any such underwriter, attorney, accountant or agent, unless such disclosure
     is made in connection with a court proceeding or required by law, or such
     information becomes available to the public generally or through a third
     party without an accompanying obligation of confidentiality;

          (iii) make such representations and warranties to the Holders of
     Securities registered thereunder and the underwriters, if any, in form,
     substance and scope as are customarily made by issuers to underwriters in
     primary underwritten offerings and covering matters including, but not
     limited to, those set forth in the Purchase Agreement;

          (iv) obtain opinions of counsel to the Company and updates thereof
     (which counsel and opinions (in form, scope and substance) shall be
     reasonably satisfactory to the Managing Underwriters, if any) addressed to
     each selling Holder and the underwriters, if any, covering such matters as
     are customarily covered in opinions requested in underwritten offerings and
     such other matters as may be reasonably requested by such Holders and
     underwriters;

          (v)   obtain "cold comfort" letters and updates thereof from the
     independent certified public accountants of the Company (and, if necessary,
     any other independent certified public accountants of any subsidiary of the
     Company or of any business acquired by the Company for which financial
     statements and financial data are, or are required to be, included in the
     Registration Statement), addressed to each selling Holder of Securities
     registered thereunder and the underwriters, if any, who have provided such
     accountants with a representation letter if required to do so under
     Statement on Auditing Standards No. 72 in customary form and covering
     matters of the type customarily covered in "cold comfort" letters in
     connection with primary underwritten offerings;

          (vi)  deliver such documents and certificates as may be reasonably
     requested by the Majority Holders and the Managing Underwriters, if any,
     including those to evidence compliance with Section 4(k) and with any
     customary conditions

                                      14
<PAGE>

     contained in the underwriting agreement or other agreement entered into by
     the Company; and

          (vii) after the Effective Time of the Shelf Registration Statement,
     upon the request of any Holder, promptly send a Notice and Questionnaire to
     such Holder; provided that the Company shall not be required to take any
     action to name such Holder as a selling securityholder in the Shelf
     Registration Statement or to enable such holder to use the prospectus
     forming a part thereof for resales of Securities except in accordance with
     Section 3(c) hereof.

The actions set forth in clauses (iii), (iv), (v) and (vi) of this Section shall
be performed at (A) the effectiveness of such Registration Statement and each
post-effective amendment thereto; and (B) each closing under any underwriting or
similar agreement as and to the extent required thereunder.

     (s)  In the case of any Exchange Offer Registration Statement, the Company
shall:

          (i)   make reasonably available for inspection by each Purchaser, and
     any attorney, accountant or other agent retained by such Purchaser, all
     relevant financial and other records, pertinent corporate documents and
     properties of the Company and its subsidiaries;

          (ii)  cause the Company's officers, directors and employees to supply
     all relevant information reasonably requested by such Purchaser or any such
     attorney, accountant or agent in connection with any such Registration
     Statement as is customary for similar due diligence examinations; provided,
                                                                       --------
     however, that any information that is designated in writing by the Company,
     -------
     in good faith, as confidential at the time of delivery of such information
     shall be kept confidential by such Purchaser or any such attorney,
     accountant or agent, unless such disclosure is made in connection with a
     court proceeding or required by law, or such information becomes available
     to the public generally or through a third party without an accompanying
     obligation of confidentiality;

          (iii) make such representations and warranties to such Purchaser, in
     form, substance and scope as are customarily made by issuers to
     underwriters in primary underwritten offerings and covering matters
     including, but not limited to, those set forth in the Purchase Agreement;

          (iv)  obtain opinions of counsel to the Company and updates thereof
     (which counsel and opinions (in form, scope and substance) shall be
     reasonably satisfactory to such Purchaser and its counsel, addressed to
     such Purchaser, covering such matters as are customarily covered in
     opinions requested in underwritten offerings and such other matters as may
     be reasonably requested by such Purchaser or its counsel;

          (v)   obtain "cold comfort" letters and updates thereof from the
     independent certified public accountants of the Company (and, if necessary,
     any other independent certified public accountants of any subsidiary of the
     Company or of any business acquired by the Company for which financial
     statements and financial data are,

                                      15
<PAGE>

     or are required to be, included in the Registration Statement), addressed
     to such Purchaser, in customary form and covering matters of the type
     customarily covered in "cold comfort" letters in connection with primary
     underwritten offerings as permitted by Statement on Auditing Standards No.
     72, or if requested by such Purchaser or its counsel in lieu of a "cold
     comfort" letter, an agreed-upon procedures letter under Statement on
     Auditing Standards No. 35, covering matters requested by such Purchaser or
     its counsel; and

          (vi)  deliver such documents and certificates as may be reasonably
     requested by such Purchaser or its counsel, including those to evidence
     compliance with Section 4(k) and with conditions customarily contained in
     underwriting agreements.

The foregoing actions set forth in clauses (iii), (iv), (v), and (vi) of this
Section shall be performed at the close of the Registered Exchange Offer and the
effective date of any post-effective amendment to the Exchange Offer
Registration Statement.

     (t)  If a Registered Exchange Offer is to be consummated, upon delivery of
the Securities by Holders to the Company (or to such other Person as directed by
the Company) in exchange for the New Securities, the Company shall mark, or
caused to be marked, on the Securities so exchanged that such Securities are
being canceled in exchange for the New Securities. In no event shall the
Securities be marked as paid or otherwise satisfied.

     (u)  The Company will use its reasonable best efforts (i) if the Securities
have been rated prior to the initial sale of such Securities, to confirm such
ratings will apply to the Securities or the New Securities, as the case may be,
covered by a Registration Statement; or (ii) if the Securities were not
previously rated, to cause the Securities covered by a Registration Statement to
be rated with at least one nationally recognized statistical rating agency, if
so requested by Majority Holders with respect to the related Registration
Statement or by any Managing Underwriters.

     (v)  In the event that any Broker-Dealer shall underwrite any Securities or
participate as a member of an underwriting syndicate or selling group or "assist
in the distribution" (within the meaning of the Rules of Fair Practice and the
By-Laws of the National Association of Securities Dealers, Inc.) thereof,
whether as a Holder of such Securities or as an underwriter, a placement or
sales agent or a broker or dealer in respect thereof, or otherwise, assist such
Broker-Dealer in complying with the requirements of such Rules and By-Laws,
including, without limitation, by:

          (i)   if such Rules or By-Laws shall so require, engaging a "qualified
     independent underwriter" (as defined in such Rules) to participate in the
     preparation of the Registration Statement, to exercise usual standards of
     due diligence with respect thereto and, if any portion of the offering
     contemplated by such Registration Statement is an underwritten offering or
     is made through a placement or sales agent, to recommend the yield of such
     Securities;

          (ii)  indemnifying any such qualified independent underwriter to the
     extent of the indemnification of underwriters provided in Section 7 hereof;
     and

                                      16
<PAGE>

          (iii) providing such information to such Broker-Dealer as may be
   required in order for such Broker-Dealer to comply with the requirements of
   such Rules.

     (w)  The Company shall use its reasonable best efforts to take all other
steps necessary to effect the registration of the Securities or the New
Securities, as the case may be, covered by a Registration Statement.

     5.  Registration Expenses. The Company shall bear all expenses incurred in
         ---------------------
connection with the performance of its obligations under Sections 2, 3 and 4
hereof and, in the event of any Shelf Registration Statement, will reimburse the
Holders for the reasonable fees and disbursements of one firm or counsel
designated by the Majority Holders to act as counsel for the Holders in
connection therewith, and, in the case of any Exchange Offer Registration
Statement, will reimburse the Purchasers for the reasonable fees and
disbursements of one firm or counsel acting in connection therewith.
Notwithstanding the foregoing, the Holders shall pay all agency fees and
commissions and underwriting discounts and commissions and the fees and
disbursements of any counsel or other advisors or experts retained by such
Holders (severally or jointly), other than the counsel specifically referred to
above.

     6.  Special Interest Under Certain Circumstances. The Company, the
         --------------------------------------------
Purchasers and each Holder of Transfer Restricted Securities agree by
acquisition of such Securities that the Holders of Transfer Restricted
Securities will suffer damages if a Registration Default (as defined below)
occurs and that it would not be feasible to ascertain the extent of such damages
with precision. Accordingly, the Company, the Purchasers and each Holder of
Transfer Restricted Securities agree that the following "Special Interest" (as
defined below) provisions shall constitute liquidated damages in the event of a
"Registration Default" (as defined below) and shall constitute the sole remedy
of the Purchasers and each Holder of Transfer Restricted Securities for any
Registration Defaults.

     (a)  In accordance with the terms of the Securities, additional interest
("Special Interest") with respect to the Securities and New Securities shall be
assessed as follows if any of the following events occur (each such event in
clauses (i) through (iv) below being herein called a "Registration Default"):

          (i)   on or prior to the 90th day following the Issue Date, neither
   the Exchange Offer Registration Statement nor the Shelf Registration
   Statement has been filed with the Commission;

          (ii)  on or prior to the 180th day following the Issue Date, neither
   the Exchange Offer Registration Statement nor the Shelf Registration
   Statement has been declared effective;

          (iii) on or prior to the 225th day following the Issue Date, neither
   the Registered Exchange Offer has been consummated nor the Shelf Registration
   Statement has been declared effective; or

          (iv)  any Registration Statement required by this Agreement has been
   declared effective by the Commission but (A) such Registration Statement
   thereafter ceases to be effective or (B) such Registration Statement or the
   related prospectus ceases

                                       17
<PAGE>

   to be usable in connection with resales of Transfer Restricted Securities
   during the periods specified herein because either (1) any event occurs as a
   result of which the related prospectus forming part of such Registration
   Statement would include any untrue statement of a material fact or omit to
   state any material fact necessary to make the statements therein in the light
   of the circumstances under which they were made not misleading, or (2) it
   shall be necessary to amend such Registration Statement or supplement the
   related prospectus, to comply with the Act or the Exchange Act or the
   respective rules thereunder;

   Each of the foregoing shall constitute a Registration Default whatever the
reason for any such event and whether it is voluntary or involuntary or is
beyond the control of the Company or pursuant to operation of law or as a result
of any action or inaction by the Commission; provided, however, that the Company
                                             --------  -------
shall in no event be required to pay liquidated damages for more than one
Registration Default at any given time.

     Special Interest shall accrue on the Securities or New Securities, as the
case may be, over and above the interest set forth in the title of the
Securities from and including the date on which any such Registration Default
shall occur to but excluding the date on which all such Registration Defaults
shall have been cured, at a rate of 0.25% per annum (the "Special Interest
Rate") for the first 90-day period immediately following the occurrence of such
Registration Default. The Special Interest Rate shall increase by an additional
0.25% per annum with respect to each subsequent 90-day period until all
Registration Defaults have been cured, up to a maximum Special Interest Rate of
1.0% per annum.

     (b)  Any amounts of Special Interest due pursuant to Section 6(a) will be
payable in cash on the regular interest payment dates with respect to the
Securities. The amount of Special Interest will be determined by multiplying the
applicable Special Interest Rate by the principal amount of the Securities and
further multiplied by a fraction, the numerator of which is the number of days
such Special Interest Rate was applicable during such period (determined on the
basis of a 360-day year comprised of twelve 30-day months), and the denominator
of which is 360.

     7.  Indemnification and Contribution. (a) The Company agrees to indemnify
         --------------------------------
and hold harmless each Holder of Securities or New Securities, as the case may
be, covered by any Registration Statement (including each Purchaser and, with
respect to any Prospectus delivery as contemplated in Section 4(h) hereof, each
Exchanging Dealer), the directors, officers, employees and agents of each such
Holder and each Person who controls any such Holder within the meaning of either
the Act or the Exchange Act against any and all losses, claims, damages or
liabilities, joint or several, to which they or any of them may become subject
under the Act, the Exchange Act or other Federal or state statutory law or
regulation, at common law or otherwise, insofar as such losses, claims, damages
or liabilities (or actions in respect thereof) arise out of or are based upon
any untrue statement or alleged untrue statement of a material fact contained in
the Registration Statement as originally filed or in any amendment thereof, or
in any preliminary Prospectus or the Prospectus, or in any amendment thereof or
supplement thereto, or arise out of or are based upon the omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, and agrees to reimburse
each such indemnified party, as incurred, for any legal or other expenses
reasonably

                                       18
<PAGE>

incurred by them in connection with investigating or defending any such loss,
claim, damage, liability or action; provided, however, that the Company will not
                                    --------  -------
be liable in any case to the extent that any such loss, claim, damage or
liability arises out of or is based upon any such untrue statement or alleged
untrue statement or omission or alleged omission made therein in reliance upon
and in conformity with written information furnished to the Company by or on
behalf of any such Holder specifically for inclusion therein. This indemnity
agreement will be in addition to any liability which the Company may otherwise
have.

     The Company also agrees to indemnify or contribute as provided in Section
7(d) to Losses of any underwriter of Securities or New Securities, as the case
may be, registered under a Shelf Registration Statement, their directors,
officers, employees or agents and each Person who controls such underwriter on
substantially the same basis as that of the indemnification of the Purchasers
and the selling Holders provided in this Section 7(a) and shall, if requested by
any Holder, enter into an underwriting agreement reflecting such agreement, as
provided in Section 4(p) hereof.

     (b)  Each Holder of securities covered by a Registration Statement
(including each Purchaser and, with respect to any Prospectus delivery as
contemplated in Section 4(h) hereof, each Exchanging Dealer) severally agrees to
indemnify and hold harmless the Company each of its directors each of its
officers who signs such Registration Statement and each Person who controls the
Company within the meaning of either the Act or the Exchange Act, to the same
extent as the foregoing indemnity from the Company to each such Holder, but only
with reference to written information relating to such Holder furnished to the
Company by or on behalf of such Holder specifically for inclusion in the
documents referred to in the foregoing indemnity. This indemnity agreement will
be in addition to any liability which any such Holder may otherwise have.

     (c)  Promptly after receipt by an indemnified party under this Section 7 of
notice of the commencement of any action, such indemnified party will, if a
claim in respect thereof is to be made against the indemnifying party under this
Section, notify the indemnifying party in writing of the commencement thereof;
but the failure so to notify the indemnifying party (i) will not relieve it from
liability under paragraph (a) or (b) above unless and to the extent it did not
otherwise learn of such action and is prejudiced thereby; and (ii) will not, in
any event, relieve the indemnifying party from any obligations to any
indemnified party other than the indemnification obligation provided in
paragraph (a) or (b) above. The indemnifying party shall be entitled to appoint
counsel of the indemnifying party's choice at the indemnifying party's expense
to represent the indemnified party in any action for which indemnification is
sought (in which case the indemnifying party shall not thereafter be responsible
for the fees and expenses of any separate counsel retained by the indemnified
party or parties except as set forth below); provided, however, that such
                                             --------  -------
counsel shall be reasonably satisfactory to the indemnified party.
Notwithstanding the indemnifying party's election to appoint counsel to
represent the indemnified party in an action, the indemnified party shall have
the right to employ separate counsel (including local counsel), and the
indemnifying party shall bear the reasonable fees, costs and expenses of such
separate counsel if (i) the use of counsel chosen by the indemnifying party to
represent the indemnified party would present such counsel with a conflict of
interest; (ii) the actual or potential defendants in, or targets of, any such
action include both the indemnified party and the indemnifying party and the
indemnified party shall have reasonably

                                       19
<PAGE>

concluded that there may be legal defenses available to it and/or other
indemnified parties which are different from or additional to those available to
the indemnifying party; (iii) the indemnifying party shall not have employed
counsel satisfactory to the indemnified party to represent the indemnified party
within a reasonable time after notice of the institution of such action; or (iv)
the indemnifying party shall authorize the indemnified party to employ separate
counsel at the expense of the indemnifying party. An indemnifying party will
not, without the prior written consent of the indemnified parties, settle or
compromise or consent to the entry of any judgment with respect to any pending
or threatened claim, action, suit or proceeding in respect of which
indemnification or contribution may be sought hereunder (whether or not the
indemnified parties are actual or potential parties to such claim or action)
unless such settlement, compromise or consent includes (i) an unconditional
release of each indemnified party from all liability arising out of such claim,
action, suit or proceeding and (ii) does not include a statement as to or an
admission of fault or failure to act by or on behalf of any indemnified party.
No indemnifying party shall be liable under subsections (a), (b) or (c) of this
Section for any settlement of any claim or action effected without its consent,
which consent will not be unreasonably withheld; provided, however, that such
                                                 --------  -------
indemnifying party has notified in writing the indemnified party of its refusal
to accept such settlement within 30 days of its receipt of a notice from the
indemnified party outlining the terms of such settlement.

     (d)  In the event that the indemnity provided in paragraph (a) or (b) of
this Section is unavailable to or insufficient to hold harmless an indemnified
party for any reason, then each applicable indemnifying party shall have a joint
and several obligation to contribute to the aggregate losses, claims, damages
and liabilities (including legal or other expenses reasonably incurred in
connection with investigating or defending same) (collectively "Losses") to
which such indemnified party may be subject in such proportion as is appropriate
to reflect the relative benefits received by such indemnifying party, on the one
hand, and such indemnified party, on the other hand, from the Initial Placement
and the Registration Statement which resulted in such Losses; provided, however,
                                                              --------  -------
that in no case shall any Purchaser of any Security or New Security be
responsible, in the aggregate, for any amount in excess of the purchase discount
or commission applicable to such Security, or in the case of a New Security,
applicable to the Security that was exchangeable into such New Security, as set
forth in the Final Memorandum, nor shall any underwriter be responsible for any
amount in excess of the underwriting discount or commission applicable to the
securities purchased by such underwriter under the Registration Statement which
resulted in such Losses, nor shall any subsequent Holder of any Security or New
Security be responsible, in the aggregate, for any amount in excess of the net
proceeds received by such Holder from the resale of such securities under the
Registration Statement which resulted in such Losses. If the allocation provided
by the immediately preceding sentence is unavailable for any reason, the
indemnifying party and the indemnified party shall contribute in such proportion
as is appropriate to reflect not only such relative benefits but also the
relative fault of such indemnifying party, on the one hand, and such indemnified
party, on the other hand, in connection with the statements or omissions which
resulted in such Losses as well as any other relevant equitable considerations.
Benefits received by the Company shall be deemed to be equal to the sum of (x)
the total net proceeds from the Initial Placement (before deducting expenses) as
set forth in the Final Memorandum and (y) the total amount of additional
interest which the Company was not required to pay as a result of registering
the securities covered by the Registration Statement which resulted in such
Losses. Benefits received by the Purchasers shall be deemed to be equal to the
total purchase discounts and commissions as set forth in the

                                       20
<PAGE>

Final Memorandum, and benefits received by any other Holders shall be deemed to
be equal to the value of receiving Securities or New Securities, as applicable,
registered under the Act. Benefits received by any underwriter shall be deemed
to be equal to the total underwriting discounts and commissions, as set forth on
the cover page of the Prospectus forming a part of the Registration Statement
which resulted in such Losses. Relative fault shall be determined by reference
to, among other things, whether any alleged untrue statement or omission relates
to information provided by the indemnifying party, on the one hand, or by the
indemnified party, on the other hand, the intent of the parties and their
relative knowledge, access to information and opportunity to correct or prevent
such untrue statement or omission. The parties agree that it would not be just
and equitable if contribution were determined by pro rata allocation (even if
the Holders were treated as one entity for such purpose) or any other method of
allocation which does not take account of the equitable considerations referred
to above. Notwithstanding the provisions of this paragraph (d), no Person guilty
of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act)
shall be entitled to contribution from any Person who was not guilty of such
fraudulent misrepresentation. For purposes of this Section, each Person who
controls a Holder within the meaning of either the Act or the Exchange Act and
each director, officer, employee and agent of such Holder shall have the same
rights to contribution as such Holder, and each Person who controls the Company
within the meaning of either the Act or the Exchange Act, each officer of the
Company who shall have signed the Registration Statement and each director of
the Company shall have the same rights to contribution as the Company, subject
in each case to the applicable terms and conditions of this paragraph (d).

     (e)  The provisions of this Section will remain in full force and effect,
regardless of any investigation made by or on behalf of any Holder or the
Company or any of the officers, directors or controlling Persons referred to in
this Section hereof, and will survive the sale by a Holder of securities covered
by a Registration Statement.

     8.  Underwritten Registrations. In connection with any Shelf Registration
         --------------------------
Statement required under this Agreement, the Company may enter into one or more
underwriting agreements, engagement letters, agency agreements, "best efforts"
underwriting agreements or similar agreements, as appropriate, including
customary provisions relating to indemnification and contribution, and take such
other actions in connection therewith as the Majority Holders shall request in
order to expedite or facilitate the disposition of such Securities.

     (a)  If any of the Securities or New Securities, as the case may be,
covered by any Shelf Registration Statement are to be sold in an underwritten
offering, the Managing Underwriters shall be selected by the Majority Holders
provided that such Managing Underwriters shall be reasonably satisfactory to the
Company.

     (b)  No Person may participate in any underwritten offering pursuant to any
Shelf Registration Statement, unless such Person (i) agrees to sell such
Person's Securities or New Securities, as the case may be, on the basis
reasonably provided in any underwriting arrangements approved by the Persons
entitled hereunder to approve such arrangements; and (ii) completes and executes
all questionnaires, powers of attorney, indemnities, underwriting agreements and
other documents reasonably required under the terms of such underwriting
arrangements.

                                       21
<PAGE>

     9.  No Inconsistent Agreements. The Company has not, as of the date hereof,
         --------------------------
entered into, nor shall it, on or after the date hereof, enter into, any
agreement with respect to its securities that is inconsistent with the rights
granted to the Holders herein or otherwise conflicts with the provisions hereof.

     10. Amendments and Waivers. The provisions of this Agreement, including the
         ----------------------
provisions of this sentence, may10. not be amended, qualified, modified or
supplemented, and waivers or consents to departures from the provisions hereof
may not be given, unless the Company has obtained the written consent of the
Majority Holders (or, after the consummation of any Registered Exchange Offer in
accordance with Section 2 hereof, of New Securities); provided that, with
respect to any matter that directly or indirectly affects the rights of any
Purchaser hereunder, the Company shall obtain the written consent of each such
Purchaser against which such amendment, qualification, supplement, waiver or
consent is to be effective. Notwithstanding the foregoing (except the foregoing
proviso), a waiver or consent to departure from the provisions hereof with
respect to a matter that relates exclusively to the rights of Holders whose
Securities or New Securities, as the case may be, are being sold pursuant to a
Registration Statement and that does not directly or indirectly affect the
rights of other Holders may be given by the Majority Holders, determined on the
basis of Securities or New Securities, as the case may be, being sold rather
than registered under such Registration Statement.

     11. Notices. All notices and other communications provided for or permitted
         -------
hereunder shall be made in writing by hand-delivery, first-class mail, telex,
telecopier or air courier guaranteeing overnight delivery:

     (a)  if to a Holder, at the most current address given by such holder to
the Company in accordance with the provisions of this Section, which address
initially is, with respect to each Holder, the address of such Holder maintained
by the Registrar under the Indenture, with copies in like manner to each of
Salomon Smith Barney Inc. and Donaldson, Lufkin, Jenrette Securities
Corporation.

     (b)  if to you, initially at the respective addresses set forth in the
Purchase Agreement; and

     (c)  if to the Company, initially at its address set forth in the Purchase
Agreement with a copy to Company counsel at the following address:

     Hale and Dorr LLP
     60 State Street
     Boston, MA  02109-1803
     Attn:  David E. Redlick
     Tel:  (617) 526-6000
     Facsimile:  (617) 526-5000

     All such notices and communications shall be deemed to have been duly given
when received.

     The Purchasers or the Company by notice to the other parties may designate
additional or different addresses for subsequent notices or communications.

                                       22
<PAGE>

     12. Successors. This Agreement shall inure to the benefit of and be binding
         ----------
upon the successors and assigns of each of the parties, including, without the
need for an express assignment or any consent by the Company thereto, subsequent
Holders of Securities and the New Securities. The Company hereby agrees to
extend the benefits of this Agreement to any Holder of Securities and the New
Securities, and any such Holder may specifically enforce the provisions of this
Agreement as if an original party hereto. At such time as Credit Suisse First
Boston Corporation succeeds to the business of Donaldson, Lufkin, Jenrette
Securities Corporation, whether by merger, sale of assets or otherwise, Credit
Suisse First Boston shall be considered a successor of Donaldson, Lufkin,
Jenrette Securities Corporation.

     13. Counterparts. This agreement may be in signed counterparts, each of
         ------------
which shall an original and all of which together shall constitute one and the
same agreement.

     14. Headings. The headings used herein are for convenience only and shall
         --------
not affect the construction hereof.

     15. Applicable Law. This Agreement shall be governed by and construed in
         --------------
accordance with the laws of the State of New York applicable to contracts made
and to be performed in the State of New York.

     16. Severability. In the event that any one of more of the provisions
         ------------
contained herein, or the application thereof in any circumstances, is held
invalid, illegal or unenforceable in any respect for any reason, the validity,
legality and enforceability of any such provision in every other respect and of
the remaining provisions hereof shall not be in any way impaired or affected
thereby, it being intended that all of the rights and privileges of the parties
shall be enforceable to the fullest extent permitted by law.

     17. Securities Held by the Company, Etc. Whenever the consent or approval
         -----------------------------------
of Holders of a specified percentage of principal amount of Securities or New
Securities is required hereunder, Securities or New Securities, as applicable,
held by the Company or its Affiliates (other than subsequent Holders of
Securities or New Securities if such subsequent Holders are deemed to be
Affiliates solely by reason of their holdings of such Securities or New
Securities) shall not be counted in determining whether such consent or approval
was given by the Holders of such required percentage.

                                       23
<PAGE>

     If the foregoing is in accordance with your understanding of our agreement,
please sign and return to us the enclosed duplicate hereof, whereupon this
letter and your acceptance shall represent a binding agreement among the Company
and the several Purchasers.

                                        Very truly yours,

                                        AMERICAN TOWER CORPORATION

                                        By:
                                           ------------------------------------
                                           Name:
                                           Title:

                                       24
<PAGE>

The foregoing Agreement is hereby confirmed and accepted as of the date first
above written.

Donaldson, Lufkin & Jenrette Securities Corporation
Salomon Smith Barney Inc.
Deutsche Banc Alex. Brown Inc.
Goldman, Sachs & Co.
Lehman Brothers Inc.
TD Securities (USA) Inc.
BNY Capital Markets, Inc.
Chase Securities Inc.
RBC Dominion Securities Corporation
Scotia Capital (USA) Inc.
Banc of America Securities LLC
BMO Nesbitt Burns Inc.
Credit Lyonnais Securities (USA) Inc.
McDonald Investments Inc.
Thomas Weisel Partners LLC

By: Donaldson, Lufkin, Jenrette Securities Corporation

By:
   -----------------------
   Name:
   Title:

- and-

By: Salomon Smith Barney Inc.

By:
   -----------------------
   Name:
   Title:

For themselves and the other several Purchasers named in Schedule I to the
Purchase Agreement and the Reallocation Purchasers named in and Annex I of the
Letter Agreement.

                                       25
<PAGE>

                                                                         ANNEX A

     Each Broker-Dealer that receives New Securities for its own account
pursuant to the Exchange Offer must acknowledge that it will deliver a
prospectus in connection with any resale of such New Securities. The Letter of
Transmittal states that by so acknowledging and by delivering a prospectus, a
Broker-Dealer will not be deemed to admit that it is an "underwriter: within the
meaning of the Act. This Prospectus, as it may be amended or supplemented from
time to time, may be used by a Broker-Dealer in connection with resales of New
Securities received in exchange for Securities where such Securities were
acquired by such Broker-Dealer as a result of market-making activities or other
trading activities. The Company has agreed that, starting on the Expiration Date
(as defined herein) and ending on the close of business 180 days after the
Expiration Date, it will make this Prospectus available to any Broker-Dealer for
use in connection with any such resale. See "Plan of Distribution".

                                       26
<PAGE>

                                                                         ANNEX B

     Each Broker-Dealer that receives New Securities for its own account in
exchange for Securities, where such Securities were acquired by such
Broker-Dealer as a result of market-making activities or other trading
activities, must acknowledge that it will deliver a prospectus in connection
with any resale of such New Securities. See "Plan of Distribution".

                                       27
<PAGE>

                                                                         ANNEX C

                             PLAN OF DISTRIBUTION

     Each Broker-Dealer that receives New Securities for its own account
pursuant to the Exchange Offer must acknowledge that it will deliver a
prospectus in connection with any resale of such New Securities. This
Prospectus, as it may be amended or supplemented from time to time, may be used
by a Broker-Dealer in connection with resales of New Securities received in
exchange for Securities where such Securities were acquired as a result of
market-making activities or other trading activities. The Company has agreed
that, starting on the Expiration Date and ending on the close of business 180
days after the Expiration Date, it will make this Prospectus, as amended or
supplemented, available to any Broker-Dealer for use in connection with any such
resale. In addition, until date that 180 days from Issue Date, 2001 all dealers
effecting transactions in the New Securities may be required to deliver a
prospectus.

     The Company will not receive any proceeds from any sale of New Securities
by brokers-dealers. New Securities received by Broker-Dealers for their own
account pursuant to the Exchange Offer may be sold from time to time in one or
more transactions in the over-the-counter market, in negotiated transactions,
through the writing of options on the New Securities or a combination of such
methods of resale, at market prices prevailing at the time of resale, at prices
related to such prevailing market prices or negotiated prices. Any such resale
may be made directly to purchasers or to or through brokers or dealers who may
receive compensation in the form of commissions or concessions from any such
Broker-Dealer and/or the purchasers of any such New Securities. Any
Broker-Dealer that resells New Securities that were received by it for its own
account pursuant to the Exchange Offer and any broker or dealer that
participates in a distribution of such New Securities may be deemed to be an
"underwriter" within the meaning of the Act and any profit of any such resale of
New Securities and any commissions or concessions received by any such Persons
may be deemed to be underwriting compensation under the Act. The Letter of
Transmittal states that by acknowledging that it will deliver and by delivering
a prospectus, a Broker-Dealer will not be deemed to admit that it is an
"underwriter" within the meaning of the Act.

     For a period of 180 days after the Expiration Date, the Company will
promptly send additional copies of this Prospectus and any amendment or
supplement to this Prospectus to any Broker-Dealer that requests such documents
in the Letter of Transmittal. The Company has agreed to pay all expenses
incident to the Exchange Offer (including the expenses of one counsel for the
holder of the Securities) other than commissions or concessions of any brokers
or dealers and will indemnify the holders of the Securities (including any
Broker-Dealers) against certain liabilities, including liabilities under the
Act.

                                       28
<PAGE>

                                                                         ANNEX D

Rider A
-------

          CHECK HERE IF YOU ARE A BROKER-DEALER AND WISH TO RECEIVE 10
          ADDITIONAL COPIES OF THE PROSPECTUS AND 10 COPIES OF ANY AMENDMENTS OR
          SUPPLEMENTS THERETO.

          Name:
                    --------------------------------------------
          Address:
                    --------------------------------------------

                    --------------------------------------------

Rider B
-------

If the undersigned is not a Broker-Dealer, the undersigned represents that it
acquired the New Securities in the ordinary course of its business, it is not
engaged in, and does not intend to engage in, a distribution of New Securities
and it has not made arrangements or understandings with any Person to
participate in a distribution of the New Securities. If the undersigned is a
Broker-Dealer that will receive New Securities for its own account in exchange
for Securities, it represents that the Securities to be exchanged for New
Securities were acquired by it as a result of market-making activities or other
trading activities and acknowledges that it will deliver a prospectus in
connection with any resale of such New Securities; however, by so acknowledging
and by delivering a prospectus, the undersigned will not be deemed to admit that
it is an "underwriter" within the meaning of the Act.

                                       29
<PAGE>

                          AMERICAN TOWER CORPORATION

                        INSTRUCTION TO DTC PARTICIPANTS

                               (Date of Mailing)
                    URGENT -- IMMEDIATE ATTENTION REQUESTED
                         DEADLINE FOR RESPONSE: [DATE]

The Depositary Trust Company ("DTC") has identified you as a DTC Participant
through which beneficial interests in the American Tower Corporation (the
"Company") 9?% Senior Notes due 2009 (the "Securities") are held.

The Company is in the process of registering the Securities under the Securities
Act of 1933 for resale by the beneficial owners thereof. In order to have their
Securities included in the registration statement, beneficial owners must
complete and return the enclosed Notice of Registration Statement and Selling
Securityholder Questionnaire.

It is important that beneficial owners of the Securities receive a copy of the
enclosed materials as soon as possible as their rights to have the Securities
included in the registration statement depend upon their returning the Notice
and Questionnaire by [DEADLINE FOR RESPONSE]. Please forward a copy of the
enclosed documents to each beneficial owner that holds interest in the
Securities through you. If you require more copies of the enclosed materials or
have any questions pertaining to this matter, please contact American Tower
Corporation, 116 Huntington Avenue, 11th Floor, Boston, MA 02116, Attention:
General Counsel.
<PAGE>

                          AMERICAN TOWER CORPORATION

                 (Notice of Registration Statement and Selling
                         Securityholder Questionnaire
                                    (Date)

Reference is hereby made to the Registration Rights Agreement (the "Registration
Rights Agreement") between American Tower Corporation (the "Company") and the
Purchasers named therein. Pursuant to the American Tower Corporation
Registration Rights Agreement, the Company has filed with the United States
Securities and Exchange Commission (the "Commission") a registration statement
on Form ___ (the "Shelf Registration Statement") for the registration and resale
under Rule 415 of the Securities Act of 1933, as amended (the "Securities Act"),
of the Company's 9?% Senior Notes due 2009, (the "Securities"). A copy of the
Registration Rights Agreement is attached hereto. All capitalized terms not
otherwise defined herein shall have the meanings ascribed thereto in the
Registration Rights Agreement.

Each beneficial owner of Transfer Restricted Securities (as defined below) is
entitled to have the Transfer Restricted Securities beneficially owned by it
included in the Shelf Registration Statement. In order to have Transfer
Restricted Securities included in the Shelf Registration Statement, this Notice
of Registration Statement and Selling Securityholder Questionnaire ("Notice and
Questionnaire") must be completed, executed and delivered to the Company's
counsel of the address set forth herein for receipt ON OR BEFORE [DEADLINE FOR
RESPONSE]. Beneficial owners of Transfer Restricted Securities who do not
complete, execute and return this Notice and Questionnaire by such date (i) will
not be named as selling securityholders in the Shelf and Registration Statement
and (ii) may not use the Prospectus forming a part thereof for resales of
Transfer Securities.

Certain legal consequences arise from being named as a selling securityholder in
the Shelf Registration Statement and related Prospectus. Accordingly, holders
and beneficial owners of Transfer Restricted Securities are advised to consult
their own securities law counsel regarding the consequence of being name or not
being named as a selling securityholder in the Shelf Registration Statement and
related Prospectus.

The term "TRANSFER RESTRICTED SECURITIES" is defined in the Registration Rights
Agreement.

                                       2
<PAGE>

                                   ELECTION

The undersigned holder (the "Selling Securityholder") of Transfer Restricted
Securities hereby elects to include in the Shelf Registration Statement the
Transfer Restricted Securities beneficially owned by it and listed below in Item
(3). The undersigned, by signing and returning this Notice and Questionnaire,
agrees to be bound with respect to such Transfer Restricted Securities by the
terms and conditions of this Notice and Questionnaire and the Registration
Rights Agreement, as if the undersigned Selling Securityholder were an original
party thereto.

Upon any sale of Transfer Restricted Securities pursuant to the Shelf
Registration Statement, the Selling Securityholder will be required to deliver
to the Company and Trustee the Notice of Transfer set forth as Annex F to the
Registration Rights Agreement. The Selling Securityholder hereby provides the
following information to the Company and represents and warrants that such
information is accurate and complete:

                                       3
<PAGE>

                                 QUESTIONNAIRE

(1)  (a)  Full Legal Name of Selling Securityholder:

     (b)  Full Legal Name of Holder (if not the same as in (a) above) of
          Transfer Restricted Securities Listed in Item (3) below:

     (c)  Full Legal Name of DTC Participant (if applicable and if not the same
          as (b) above) Through Which Transfer Restricted Securities Listed in
          Item (3) below are Held:

(2)  Address for Notices to Selling Securityholder:

     Telephone:
     Fax:
     Contact Person:

(3)  Beneficial Ownership of Securities:

     Except as set forth below in this Item (3), the undersigned does not
beneficially own any Securities.

     (a)  Principal amount of Transfer Restricted Securities beneficially owned:
          _____ CUSIP No(s) of such Transfer Restricted Securities_____

     (b)  Principal amount of Securities other than Transfer Restricted
          Securities beneficially owned: ____ CUSIP No(s). of such other
          Securities_____

     (c)  Principal amount of Transfer Restricted Securities which the
          undersigned wishes to be included in the Shelf Registration Statement:
          _____ CUSIP No(s). of such Transfer Restricted Securities to be
          included in the Shelf Registration Statement_____

(4)  Beneficial Ownership of other Securities of the Company:

     Except as set forth below in this Item (4), the undersigned Selling
     Securityholder is not the beneficial or registered owner of any other
     securities of the Company, other than the Securities listed above in Item
     (3).

     State any exceptions here:

(5)  Relationships with the Company:

     Except as set forth below, neither the Selling Securityholder nor any of
     its affiliates, officers, directors or principal equity holders (5% or
     more) has held any position or office or has had any other material
     relationship with the Company (or its predecessors or affiliates) during
     the past three years.

(6)  Plan of Distribution:

     State any exceptions here:

     Except as set forth below, the undersigned Selling Securityholder intends
to distribute the Transfer Restricted Securities listed above in Item (3) only
as follows (if at all): Such Transfer

                                       4
<PAGE>

Restricted Securities may be sold from time to time directly by the undersigned
Selling Securityholder or, alternatively, through underwriters, broker-dealers
or agents. Such Transfer Restricted Securities may be sold in one or more
transactions at fixed prices, at prevailing market prices at the time of sale,
at varying prices determined at the time of sale, or at negotiated prices. Such
sales may be effected in transactions (which may involve crosses or block
transactions) (i) on any national securities exchange or quotation service on
which the Registered Securities may be listed or quoted at the time of sale,
(ii) in the over-the-counter market, (iii) in transactions otherwise than on
such exchanges or services or in the over-the-counter market, or (iv) through
the writing of options. In connection with sales of the Transfer Restricted
Securities or otherwise, the Selling Securityholder may enter into hedging
transactions with broker-dealers, which may in turn engage in short sales of the
Transfer Restricted Securities in the course of hedging the positions they
assume. The Selling Securityholder may also sell Transfer Restricted Securities
short and deliver Transfer Restricted Securities to close out such short
positions, or loan or pledge Transfer Restricted Securities to broker-dealers
that in turn may sell such securities

     State any exceptions here:

By signing below, the Selling Securityholder acknowledges that it understands
its obligation to comply, and agrees that it will comply, with the provisions of
the Exchange Act and the rules and regulations thereunder, particularly
Regulation M.

In the event that the Selling Securityholder transfers all or any portion of the
Transfer Restricted Securities listed in Item (3) above after the date on which
such information is provided to the Company, the Selling Securityholder agrees
to notify the transferee(s) at the time of the transfer of its rights and
obligations under this Notice and Questionnaire and the Exchange and
Registration Rights Agreement.

By signing below, the Selling Securityholder consents to the disclosure of the
information contained herein in its answers to Items (1) through (6) above and
the inclusion of such information in the Shelf Registration Statement and
related Prospectus. The Selling Securityholder understands that such information
will be relied upon by the Company in connection with the preparation of the
Shelf Registration Statement and related Prospectus. In accordance with the
Selling Securityholder's obligation under Section 3(e) of the Exchange and
Registration Rights Agreement to provide such information as may be required by
law for inclusion in the Shelf Registration Statement, the Selling
Securityholder agrees to promptly notify the Company of any inaccuracies or
changes in the information provided herein which may occur subsequent to the
date hereof at any time while the Shelf Registration Statement remains in
effect. All notices hereunder and pursuant to the Registration Rights Agreement
shall be made in writing, by hand-delivery, or air courier guaranteeing
overnight delivery as follows:

                                       5
<PAGE>

(i)      To the Company:

         --------------------
         --------------------
         --------------------
         --------------------
         --------------------

(ii)     With a copy to:

         --------------------
         --------------------
         --------------------

Once this Notice and Questionnaire is executed by the Selling Securityholder and
received by the Company's counsel, the terms of this Notice and Questionnaire,
and the representations and warranties contained herein, shall be binding on,
shall inure to the benefit of and shall be enforceable by the respective
successors, heirs, personal representatives, and assigns of the Company and the
Selling Securityholder (with respect to the Transfer Restricted Securities
beneficially owned by such Selling Securityholder and listed in Item (3) above.
This Agreement shall be governed in all respects by the laws of the State of New
York.

                                       6
<PAGE>

IN WITNESS WHEREOF, the undersigned, by authority duly given, has caused this
Notice and Questionnaire to be executed and delivered either in person or by its
duly authorized agent.

Dated:

Selling Securityholder
(Print/type full legal name of beneficial owner of Transfer Restricted
Securities)

By:
Name:
Title:

PLEASE RETURN THE COMPLETED AND EXECUTED NOTICE AND QUESTIONNAIRE FOR RECEIPT ON
OR BEFORE [DEADLINE FOR RESPONSE] TO THE COMPANY'S COUNSEL AT:

-----------------------------
-----------------------------
-----------------------------
-----------------------------
-----------------------------
<PAGE>

                                                                         ANNEX F

Notice of Transfer Pursuant to Registration Statement

America Tower Corporation
The Bank of New York
[Address]

Attention: Trust Officer

Re:  9 3/8% Senior Notes Due 2009

Dear Sirs:

         Please be advised that ____________________has transferred
$________________ aggregate principal amount of the above-referenced Notes
pursuant to an effective Registration Statement on Form [ ] (File No. 333-    )
filed by the Company.

         We hereby certify that the prospectus delivery requirements, if any, of
the Securities Act of 1933, as amended, have been satisfied and that the
above-named beneficial owner of the Notes is named as a "Selling Holder" in the
Prospectus dated [DATE] or in supplements thereto, and that the aggregate
principal amount of the Notes transferred are the Notes listed in such
Prospectus opposite such owner's name.

Dated:

                                        Very truly yours,

                                        ----------------------------------------
                                        (Name)
                                        By: (Authorized Signature)

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