Document:

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                                                                     EXHIBIT 4.2

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                                 ADVANSTAR, INC.

                    15.0% SENIOR DISCOUNT DEBENTURES DUE 2011

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                                    INDENTURE
                          Dated as of February 21, 2001

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                       WELLS FARGO BANK MINNESOTA, N.A. as

                                     TRUSTEE

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                              CROSS-REFERENCE TABLE
                                                                   Indenture
TIA Section                                                        Section
-----------                                                        -------
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).......................................................... 10.03
      (c).......................................................... 10.03
313   (a).......................................................... 7.06
      (b)(1)....................................................... N.A.
      (b)(2)....................................................... 7.06; 7.07
      (c).......................................................... 7.06; 10.02
      (d).......................................................... 7.06
314   (a).......................................................... 10.05
      (b).......................................................... N.A.
      (c)(1)....................................................... 10.04
      (c)(2)....................................................... 10.04
      (c)(3)....................................................... N.A.
      (d).......................................................... N.A.
      (e).......................................................... 10.05
      (f).......................................................... N.A.
315   (a).......................................................... 7.01
      (b).......................................................... 7.05; 10.02
      (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; 9.02
317   (a)(1)....................................................... 6.08
      (a)(2)....................................................... 6.09
      (b).......................................................... 2.04
318   (a).......................................................... 10.01
      (b).......................................................... N.A.
      (c).......................................................... 10.01

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                                TABLE OF CONTENTS

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ARTICLE 1
       DEFINITIONS AND INCORPORATION BY REFERENCE
       SECTION 1.01.  Definitions..............................................1
       SECTION 1.02.  Other Definitions.......................................19
       SECTION 1.03.  Incorporation of TIA Provisions.........................20
       SECTION 1.04.  Rules of Construction...................................20

ARTICLE 2
       THE NOTES
       SECTION 2.01.  Form and Dating.........................................21
       SECTION 2.02.  Registrar and Paying Agent..............................22
       SECTION 2.03.  Registrar and Paying Agent..............................22
       SECTION 2.04.  Paying Agent to Hold Money in Trust.....................23
       SECTION 2.05.  Holder Lists............................................23
       SECTION 2.06.  Transfer and Exchange...................................23
       SECTION 2.07.  Replacement Notes.......................................36
       SECTION 2.08.  Outstanding Notes.......................................36
       SECTION 2.09.  Treasury Notes..........................................37
       SECTION 2.10.  Temporary Notes.........................................37
       SECTION 2.11.  Cancellation............................................37
       SECTION 2.12.  Defaulted Interest......................................37

ARTICLE 3
       REDEMPTION AND PREPAYMENT
       SECTION 3.01.  Notices to Trustees.....................................38
       SECTION 3.02.  Selection of Notes to Be Redeemed.......................38
       SECTION 3.03.  Notice of Redemption....................................38
       SECTION 3.04.  Effect of Notice of Redemption..........................39
       SECTION 3.05.  Deposit of Redemption Price.............................39
       SECTION 3.06.  Notes Redeemed in Part..................................40
       SECTION 3.07.  Optional Redemption.....................................40
       SECTION 3.08.  Mandatory Redemption....................................40
       SECTION 3.09.  Offer to Purchase by Application of Excess Proceeds.....40

ARTICLE 4
       COVENANTS
       SECTION 4.01.  Payment of Notes........................................42
       SECTION 4.02.  Maintenance of Office or Agency.........................43
       SECTION 4.03.  Reports.................................................43
       SECTION 4.04.  Compliance Certificate..................................44
       SECTION 4.05.  Taxes...................................................44
       SECTION 4.06.  Stay, Extension and Usury Laws..........................44
       SECTION 4.07.  Restricted Payments.....................................45
       SECTION 4.08.  Dividend and Other Payment Restrictions Affecting
                       Subsidiaries...........................................50

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       SECTION 4.09.  Incurrence of Indebtedness and Issuance of Preferred
                       Stock..................................................51
       SECTION 4.10.  Asset Sales.............................................53
       SECTION 4.11.  Transactions with Affiliates............................55
       SECTION 4.12.  Liens...................................................56
       SECTION 4.13.  Corporate Existence.....................................56
       SECTION 4.14.  Offer to Repurchase upon Change of Control..............56
       SECTION 4.15.  Limitation on Sale and Leaseback Transactions...........57

ARTICLE 5
       SUCCESSORS
       SECTION 5.01.  Merger, Consolidation, or Sale of Assets................58
       SECTION 5.02.  Successor Corporation Substituted.......................59

ARTICLE 6
       DEFAULTS AND REMEDIES
       SECTION 6.01.  Events of Default.......................................59
       SECTION 6.02.  Acceleration............................................61
       SECTION 6.03.  Other Remedies..........................................61
       SECTION 6.04.  Waiver of Past Defaults.................................62
       SECTION 6.05.  Control by Majority.....................................62
       SECTION 6.06.  Limitation on Suits.....................................62
       SECTION 6.07.  Rights of Holders of Notes to Receive Payment...........62
       SECTION 6.08.  Collection Suit by Trustee..............................63
       SECTION 6.09.  Trustee May File Proofs of Claim........................63
       SECTION 6.10.  Priorities..............................................64
       SECTION 6.11.  Undertaking for Costs...................................64

ARTICLE 7
       TRUSTEE
       SECTION 7.01.  Duties of Trustee.......................................64
       SECTION 7.02.  Rights of Trustee.......................................65
       SECTION 7.03.  Individual Rights of Trustee............................66
       SECTION 7.04.  Trustee's Disclaimer....................................66
       SECTION 7.05.  Notice of Defaults......................................67
       SECTION 7.06.  Reports by Trustee to Holders of the Notes..............67
       SECTION 7.07.  Compensation and Indemnity..............................67
       SECTION 7.08.  Replacement of Trustee..................................68
       SECTION 7.09.  Successor Trustee by Merger, Etc........................69
       SECTION 7.10.  Eligibility; Disqualification...........................69
       SECTION 7.11.  Preferential Collection of Claims Against Company.......69

ARTICLE 8
       LEGAL DEFEASANCE AND COVENANT DEFEASANCE
       SECTION 8.01.  Option to Effect Legal Defeasance or Covenant
                        Defeasance............................................69
       SECTION 8.02.  Legal Defeasance and Discharge..........................70
       SECTION 8.03.  Covenant Defeasance.....................................70
       SECTION 8.04.  Conditions to Legal or Covenant Defeasance..............71

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       SECTION 8.05.  Deposited Money and Government Securities to Be
              Held in Trust; Other Miscellaneous Provisions...................72
       SECTION 8.06.  Repayment to Company....................................73
       SECTION 8.07.  Reinstatement...........................................73

ARTICLE 9
       AMENDMENT, SUPPLEMENT AND WAIVER
       SECTION 9.01.  Without Consent of Holders of Notes.....................73
       SECTION 9.02.  With Consent of Holders of Notes........................74
       SECTION 9.03.  Compliance with Trust Indenture Act.....................76
       SECTION 9.04.  Revocation and Effect of Consents.......................76
       SECTION 9.05.  Notation on or Exchange of Notes........................76
       SECTION 9.06.  Trustee to Sign Amendments, Etc.........................76

ARTICLE 10
       MISCELLANEOUS
       SECTION 10.01.  Trust Indenture Act Controls...........................76
       SECTION 10.02.  Notices................................................76
       SECTION 10.03.  Communication by Holders of Notes with Other Holders
              of  Notes.......................................................78
       SECTION 10.04.  Certificate and Opinion as to Conditions Precedent.....78
       SECTION 10.05.  Statements Required in Certificate or Opinion..........78
       SECTION 10.06.  Rules by Trustee and Agents............................78
       SECTION 10.07.  No Personal Liability of Directors, Officers,
              Employees and Stockholders......................................79
       SECTION 10.08.  Governing Law..........................................79
       SECTION 10.09.  No Adverse Interpretation of Other Agreements..........79
       SECTION 10.10.  Successors.............................................79
       SECTION 10.11.  Severability...........................................79
       SECTION 10.12.  Counterpart Originals..................................79
       SECTION 10.13.  Table of Contents, Headings, Etc.......................79

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EXHIBITS
Exhibit A:        FORM OF NOTE
Exhibit B:        FORM OF CERTIFICATE OF TRANSFER
Exhibit C:        FORM OF CERTIFICATE OF EXCHANGE
Exhibit D:        FORM OF CERTIFICATE OF ACQUIRING INSTITUTIONAL
                  ACCREDITED INVESTOR

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      INDENTURE dated as of February 21, 2001, by and among Advanstar, Inc., a
Delaware corporation (the "Company"); and Wells Fargo Bank Minnesota, N.A., 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 15.0% Senior
Discount Debentures due 2011 (the "Notes").

                                    ARTICLE 1
                   DEFINITIONS AND INCORPORATION BY REFERENCE

      SECTION 1.01. Definitions.

      "144A Global Note" means the form of the Notes initially issued to QIBs.

      "Accounts Receivable Subsidiary" means an Unrestricted Subsidiary of the
Company to which the Company or any of its Restricted Subsidiaries sells any of
its accounts receivable pursuant to a Receivables Facility.

      "Accreted Value" means (i) as of any date of determination prior to
October 15, 2005, the sum of (a) the initial offering price of the Notes (which
shall be calculated by discounting from October 15, 2005 the aggregate principal
amount at maturity of the Notes at a rate of 15.0% per annum, (compounded
semiannually on each April 15 and October 15 from February 21, 2001)) and (b)
the portion of the excess of the principal amount at maturity of the Notes over
such initial offering price which shall have been accreted thereon through such
date, such amount to be accreted on a daily basis at a rate of 15.0% per annum
of the initial offering price of the Notes, compounded semi-annually on each
April 15 and October 15 from February 21, 2001 through the date of determination
and computed on the basis of a 360-day year of twelve 30-day months and (ii) as
of any date of determination on or after October 15, 2005, the aggregate
principal amount at maturity of the Notes.

      "Acquired Indebtedness" means, with respect to any specified Person, (a)
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 (b) Indebtedness secured by a Lien
encumbering an asset acquired by such specified Person at the time such asset is
acquired by such specified Person.

      "Acquisition" means the acquisition of the Company by Holdings, a newly
formed affiliate of the Principals and their Related Parties, pursuant to the
terms of the Acquisition Agreement.

      "Acquisition Agreement" means that certain Agreement and Plan of Merger
dated as of August 14, 2000 with respect to the Acquisition.

      "Acquisition Financing" means;

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            (1) the issuance and sale by Holdings of common stock for
      consideration;

            (2) the issuance and sale by the Company of the Notes;

            (3) the issuance and sale by the Company of the 15% Senior Discount
      Notes pursuant to the Securities Purchase Agreement dated as of October
      11, 2000;

            (4) the issuance by certain subsidiaries of the Company of bridge
      notes (and any Permitted Refinancing Indebtedness incurred in lieu
      thereof); and

            (5) the execution and delivery by the Company and certain of its
      subsidiaries of the New Credit Facility and the borrowing of loans and
      issuance of letters of credit thereunder to fund the Acquisition and any
      related transactions, including without limitation, the payment of fees
      and expenses and the refinancing of outstanding indebtedness of the
      Company and its Subsidiaries;

the proceeds of each of which were used to fund the purchase price for the
Acquisition, including the refinancing of outstanding indebtedness, and related
fees and expenses.

      "Affiliate" of any specified Person means any other Person which, directly
or indirectly, controls, is controlled by or is under direct or indirect common
control with, such specified Person. For purposes of this definition, "control,"
when used with respect to any Person, means the power to direct the management
and policies of such Person, directly or indirectly, whether through the
ownership of voting securities, by contract or otherwise, and the terms
"controlling" and "controlled" have meanings correlative to the foregoing.

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

      "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.

      "Asset Sale" means (a) the sale, lease, conveyance, disposition or other
transfer (a "disposition") of any properties, assets or rights (including,
without limitation, by way of a sale and leaseback) (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 the
provisions of Sections 4.14 and/or 5.01 and not by the provisions of Section
4.10), and (b) the issuance, sale or transfer by the Company or any of its
Restricted Subsidiaries of Equity Interests of any of the Company's Restricted
Subsidiaries, in the case of either clause (a) or (b), whether in a single
transaction or a series of related transactions (i) that have a fair market
value in excess of $5.0 million or (ii) for net proceeds in excess of $5.0
million. Notwithstanding the foregoing, the following items shall not be deemed
to be Asset Sales: (a) dispositions in the ordinary course of business; (b) a
disposition of assets by the Company to a Restricted Subsidiary or by a
Restricted Subsidiary to the Company or to another Restricted Subsidiary; (c) a
disposition of Equity Interests by a Restricted Subsidiary to

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the Company or to another Restricted Subsidiary; (d) the sale and leaseback of
any assets within 90 days of the acquisition thereof; (e) foreclosures on
assets; (f) any exchange of like property pursuant to Section 1031 of the
Internal Revenue Code of 1986, as amended, for use in a Permitted Business; (g)
any sale of Equity Interests in, or Indebtedness or other securities of, an
Unrestricted Subsidiary; (h) a Permitted Investment or a Restricted Payment that
is permitted by Section 4.07 hereof; and (i) sales of accounts receivable, or
participations therein, in connection with any Receivables Facility.

      "Attributable Indebtedness" 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 Expenditure Indebtedness" means Indebtedness incurred by any
Person to finance the purchase or construction or any property or assets
acquired or constructed by such Person which have a useful life of more than one
year so long as (a) the purchase or construction price for such property or
assets is included in "addition to property, plant or equipment" in accordance
with GAAP, (b) the acquisition or construction of such property or assets is not
part of any acquisition of a Person or line of business and (c) such
Indebtedness is incurred within 90 days of the acquisition or completion of
construction of such property or assets.

      "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 (a) in the case of a corporation, corporate stock,
(b) in the case of an association or business entity, any and all shares,
interests, participations, rights or other equivalents (however designated) of
corporate stock, (c) in the case of a partnership or limited liability company,
partnership or membership interests (whether general or limited) and (d) 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 (i) Government Securities, (ii) any certificate
of deposit maturing not more than 365 days after the date of acquisition issued
by, or demand deposit or time deposit of, an Eligible Institution or any lender
under the New Credit Facility, (iii) commercial paper maturing not more than 365
days after the date of

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acquisition of an issuer (other than an Affiliate of the Company) with a rating,
at the time as of which any investment therein is made, of "A-3" (or higher)
according to Standard & Poor's Rating's Group ("S&P") or "P-2" (or higher)
according to Moody's Investor Services, Inc. ("Moody's") or carrying an
equivalent rating by a nationally recognized rating agency if both of the two
named rating agencies cease publishing ratings of investments, (iv) any bankers
acceptances or money market deposit accounts issued by an Eligible Institution,
(v) short-term tax-exempt securities rated not lower than MIG- 1/1+ by either
Moody's or S&P with provisions for liquidity or maturity accommodations of 183
days or less, (vi) repurchase agreements which (x) are entered into with any
entity referred to in clauses (ii), (iii) or (iv) above or any other financial
institution whose unsecured long-term debt (or the unsecured long-term debt of
whose holding company) is rated at least A- or better by S&P or Baa1 or better
by Moody's and maturing not more than one year after such time, (y) are secured
by a fully perfected security interest in securities of the type referred to in
clause (i) above and (z) have a market value at the time of such repurchase
agreement is entered into of not less than 100% of the repurchase obligation of
such counterparty entity with whom such repurchase agreement has been entered
into, (vii) any fund investing exclusively in investments of the types described
in clauses (i) through (v) above, and (viii) in the case of any Subsidiary
organized or having its principal place of business outside the United States,
investments denominated in the currency of the jurisdiction in which such
Subsidiary is organized or has its principal place of business which are similar
to the items specified in clauses (i) through (vii) above (including without
limitation any deposit with a bank that is a lender to any Restricted
Subsidiary).

      "Change of Control" means the occurrence of any of the following: (a) 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 Subsidiaries, taken as a
whole, to any "person" or "group" (as such terms are used in Section 13(d) of
the Exchange Act), other than the Principals and their Related Parties; (b) the
adoption of a plan for the liquidation or dissolution of the Company; (c) the
consummation of any transaction (including, without limitation, any merger or
consolidation) the result of which is that any "person" or "group" (as such
terms are used in Section 13(d) of the Exchange Act), other than the Principals
and their Related Parties, becomes the "beneficial owner" (as such term is
defined in Rule 13d-3 and Rule 13d-5 under the Exchange Act), directly or
indirectly through one or more intermediaries, of 50% or more of the voting
power of the outstanding voting Equity Interests of the Company; (d) the first
day on which a majority of the members of the board of directors of the Company
are not Continuing Members; or (e) the Company shall fail to own, directly or
indirectly, 100% of the outstanding Equity Interests of Advanstar
Communications, Inc. (or any successor thereto).

      "Clearstream" means Clearstream Banking SA, a limited liability company
(la societe anonyme), organized under Luxembourg law.

      "Commission" means the Securities and Exchange Commission.

      "Company" has the meaning set forth in the preamble to this Indenture.

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      "Consolidated Cash Flow" means, with respect to any Person for any period,
the Consolidated Net Income of such Person and its Restricted Subsidiaries for
such period plus, to the extent deducted in computing Consolidated Net Income,
(a) provision for taxes based on income or profits of such Person and its
Restricted Subsidiaries for such period, (b) Fixed Charges of such Person for
such period, (c) depreciation, amortization (including amortization of goodwill
and other intangibles) and all other non-cash charges (but excluding any other
non-cash charge to the extent that it represents an accrual of or reserve for
cash expenses in any future period or amortization of a prepaid cash expense
that was paid in a prior period) of such Person and its Restricted Subsidiaries
for such period, (d) net periodic post-retirement benefits, (e) other income or
expense net as set forth on the face of such Person's statement of operations,
(f) expenses and charges of the Company related to the Acquisition and
Acquisition Financing including any purchase price adjustment or any other
payments made pursuant to the Acquisition Agreement or the financial advisory
agreements with Credit Suisse First Boston Corporation, the New Credit Facility
and the application of the proceeds thereof, and (g) any non-capitalized
transaction costs incurred in connection with actual, proposed or abandoned
financings, acquisitions or divestitures (including, but not limited to,
financing and refinancing fees and costs incurred in connection with the
Acquisition and Acquisition Financing), in each case, on a consolidated basis
and determined in accordance with GAAP. Notwithstanding the foregoing, the
provision for taxes based on the income or profits of, the Fixed Charges of, and
the depreciation and amortization and other non-cash charges of, a Restricted
Subsidiary of a Person shall be added to Consolidated Net Income to compute
Consolidated Cash Flow only to the extent (and in the same proportion) that Net
Income of such Restricted Subsidiary was included in calculating the
Consolidated Net Income of such Person.

      "Consolidated Indebtedness" means the aggregate amount of Indebtedness of
the Company and its Restricted Subsidiaries on a consolidated basis outstanding
at the date of determination.

      "Consolidated Interest Expense" means, with respect to any Person for any
period, the sum of, without duplication, (a) the interest expense of such Person
and its Restricted Subsidiaries for such period, on a consolidated basis,
determined in accordance with GAAP (including amortization of original issue
discount, non-cash interest payments, the interest component of all payments
associated with Capital Lease Obligations, imputed interest with respect to
Attributable Indebtedness, 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; provided that in no event
shall any amortization of deferred financing costs be included in Consolidated
Interest Expense); and (b) the consolidated capitalized interest of such Person
and its Restricted Subsidiaries for such period, whether paid or accrued;
provided, however, that Receivables Fees shall be deemed not to constitute
Consolidated Interest Expense. Notwithstanding the foregoing, the Consolidated
Interest Expense with respect to any Restricted Subsidiary that is not a Wholly
Owned Restricted Subsidiary shall be included only to the extent (and in the
same proportion) that the net income of such Restricted Subsidiary was included
in calculating Consolidated Net Income.

      "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

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period, on a consolidated basis, determined in accordance with GAAP; provided
that (a) the Net Income (or loss) of any Person 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, (b) the Net
Income (or loss) of any Restricted Subsidiary other than a Subsidiary organized
or having its principal place of business outside the United States shall be
excluded to the extent that the declaration or payment of dividends or similar
distributions by that Restricted Subsidiary of that Net Income (or loss) is not
at the date of determination permitted without any prior governmental approval
(that has not been obtained) or, directly or indirectly, by operation of the
terms of its charter or any agreement, instrument, judgment, decree, order,
statute, rule or governmental regulation applicable to that Restricted
Subsidiary (other than any agreement or instrument entered into by Advanstar
Communications, Inc.), (c) the Net Income (or loss) of any Person acquired in a
pooling of interests transaction for any period prior to the date of such
acquisition shall be excluded and (d) the cumulative effect of a change in
accounting principles shall be excluded.

      "Continuing Members" means, as of any date of determination, any member of
the Board of Directors who (a) was a member of such Board of Directors
immediately after consummation of the Acquisition or (b) was nominated for
election or elected to such Board of Directors with the approval of, or whose
election to the Board of Directors was ratified by, at least a majority of the
Continuing Members who were members of such Board of Directors at the time of
such nomination or election.

      "Corporate Trust Office of the Trustee" shall be at the address of the
Trustee specified in Section 10.02 hereof or such other address as to which the
Trustee may give notice to the Company.

      "Custodian" means any receiver, trustee, assignee, liquidator or similar
official under any Bankruptcy Law.

      "Date of Issuance" means February 21, 2001.

      "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, in the form of
Exhibit A-1 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 The Depository Trust Company.

      "Designated Noncash Consideration" means the fair market value of non-cash
consideration received by the Company or one of its Restricted Subsidiaries in
connection with an Asset Sale that is so designated as Designated Noncash
Consideration pursuant to an Officers' Certificate, setting forth the basis of
such valuation, executed by the principal executive officer and the principal
financial officer

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of the Company, less the amount of cash or Cash Equivalents received in
connection with a sale of such Designated Noncash Consideration.

      "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), or upon the happening of any event (other than any event solely
within the control of the issuer thereof), matures or is mandatorily redeemable,
pursuant to a sinking fund obligation or otherwise, is exchangeable for
Indebtedness (except to the extent exchangeable at the option of such Person
subject to the terms of any debt instrument to which such Person is a party) or
redeemable at the option of the Holder thereof, in whole or in part, on or prior
to the date on which the Notes mature; provided 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; and
provided further that, if such Capital Stock is issued to any plan for the
benefit of employees of the Company or its Subsidiaries or by any such plan to
such employees, such Capital Stock shall not constitute Disqualified Stock
solely because it may be required to be repurchased by the Company in order to
satisfy applicable statutory or regulatory obligations.

      "DLJMB" means DLJ Merchant Banking Partners III, L.P., its successors and
its Affiliates.

      "Domestic Subsidiary" means a Subsidiary that is organized under the laws
of the United States or any State, district or territory thereof.

      "Eligible Institution" means a commercial banking institution that has
combined capital and surplus not less than $100.0 million or its equivalent in
foreign currency, whose short-term debt is rated "A-3" or higher according to
S&P or "P-2" or higher according to Moody's or carrying an equivalent rating by
a nationally recognized rating agency if both of the two named rating agencies
cease publishing ratings of investments.

      "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 Morgan Guaranty Trust Company of New York, Brussels
office and any successor thereto, as operator of the Euroclear system.

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

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

                                       7
<PAGE>

      "Fixed Charges" means, with respect to any Person for any period, the sum,
without duplication, of (a) the Consolidated Interest Expense of such Person for
such period and (b) all dividend payments on any series of preferred stock of
such Person (other than dividends payable solely in Equity Interests that are
not Disqualified Stock), in each case, on a consolidated basis and in accordance
with GAAP.

      "Foreign Credit Facilities" means any Indebtedness of a Restricted
Subsidiary organized or having its principal place of business outside the
United States. Indebtedness under the Foreign Credit Facilities outstanding on
the Date of Issuance shall be deemed to have been incurred on such date in
reliance on the first paragraph of Section 4.09 hereof.

      "GAAP" means generally accepted accounting principles 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 of Issuance.

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

      "Global Notes" means, individually and collectively, each of the
Restricted Global Notes and the Unrestricted Global Notes, in the form of
Exhibit A hereto issued in accordance with Section 2.01, 2.06(b)(iv),
2.06(d)(ii) or 2.06(f) hereof.

      "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, 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 (a) interest rate swap agreements, interest rate cap
agreements and interest rate collar agreements and (b) other agreements or
arrangements designed to protect such Person against fluctuations in interest
rates.

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

      "Holdings" means Advanstar Holdings Corp., a Delaware corporation, the
corporate parent of the Company, or its successors.

      "Indebtedness" means, with respect to any Person, any indebtedness of such
Person 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

                                       8
<PAGE>

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 or customer contract advances, if and 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) and, to the extent not otherwise included, the guarantee by such Person
of any Indebtedness of any other Person, provided that Indebtedness shall not
include the pledge by the Company of the Capital Stock of an Unrestricted
Subsidiary of the Company to secure Non-Recourse Debt of such Unrestricted
Subsidiary. The amount of any Indebtedness outstanding as of any date shall be
(a) the accreted value thereof (together with any interest thereon that is more
than 30 days past due), in the case of any Indebtedness that does not require
current payments of interest, and (b) the principal amount thereof, in the case
of any other Indebtedness provided that the principal amount of any Indebtedness
that is denominated in any currency other than United States dollars shall be
the amount thereof, as determined pursuant to the foregoing provision, converted
into United States dollars at the Spot Rate in effect on the date that such
Indebtedness was incurred (or, if such indebtedness was incurred prior to the
Date of Issuance, the Spot Rate in effect on the Date of Issuance).

      "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.

      "Institutional Accredited Investor" means an institution that is an
"accredited investor" as defined in Rule 501(a)(1), (2), (3) or (7) under the
Securities Act, who are not also QIBs.

      "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 by the referent Person of, and Liens on any
assets of the referent Person securing, Indebtedness or other obligations of
other Persons), 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, provided that an investment by the Company for consideration consisting of
common equity securities of the Company shall not be deemed to be an Investment,
other than for purposes of clause (3) of the definition of "Qualified Proceeds."
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 such that, after giving effect to any such sale or disposition,
such Person is no longer a Subsidiary of the Company, the Company shall be
deemed to have made an Investment on the date of any such sale or disposition
equal to the fair market value of the Equity Interests of such Restricted
Subsidiary not sold or disposed of in an amount determined as provided in the
final paragraph of Section 4.07 hereof.

                                       9
<PAGE>

      "Legal Holiday" means a Saturday, a Sunday or a day on which banking
institutions in the City of New York or the city in which the principal
corporate trust office of the Trustee is located, 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.

      "Leverage Ratio" means, with respect to any Person as of any date of
determination, the ratio of (x) Consolidated Indebtedness of such Person as of
such date of determination to (y) the Consolidated Cash Flow of such Person for
the four full fiscal quarters ending on or immediately preceding such date of
determination for which internal financial statements are available (exclusive
of amounts attributable to discontinued operations, as determined in accordance
with GAAP, or operations and businesses disposed of prior to the date of
determination).

      In the event that the referent Person or any of its Subsidiaries incurs,
assumes, guarantees or redeems any Indebtedness (other than revolving credit
borrowings) or issues or redeems preferred stock subsequent to the commencement
of the period for which the Leverage Ratio is being calculated but on or prior
to the date on which the event for which the calculation of the Leverage Ratio
is made (the "Calculation Date"), then the Leverage Ratio shall be calculated
giving pro forma effect to that incurrence, assumption, guarantee or redemption
of Indebtedness, or that issuance or redemption of preferred stock and the use
of the proceeds therefrom, as if the same had occurred at the beginning of the
applicable four-quarter reference period.

      For purposes of making the computation referred to above, the Acquisition
and acquisitions that have been made by the Company or any of its Subsidiaries,
including all mergers or consolidations and any related financing transactions,
during the four-quarter reference period shall be deemed to have occurred on the
first day of the four-quarter reference period and Consolidated Cash Flow for
that reference period shall be calculated to include the Consolidated Cash Flow
of the acquired entities on a pro forma basis after giving effect to cost
savings reasonably expected to be realized in connection with that acquisition,
as determined in good faith by an officer of the Company (regardless of whether
those cost savings could then be reflected in pro forma financial statements
under GAAP, Regulation S-X promulgated by the Commission or any other regulation
or policy of the Commission) and without giving effect to clause (c) of the
proviso set forth in the definition of Consolidated Net Income.

      "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).

      "Management Loans" means one or more loans by the Company or Holdings to
officers and/or directors of the Company and any of its Restricted Subsidiaries
to finance

                                       10
<PAGE>

the purchase by such officers and directors of common stock of Holdings;
provided, however, that the aggregate principal amount of all such Management
Loans outstanding at any time shall not exceed $7.5 million.

      "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, (a) any gain (or
loss), together with any related provision for taxes on such gain (or loss),
realized in connection with (i) any Asset Sale (including, without limitation,
dispositions pursuant to sale and leaseback transactions) or (ii) the
extinguishment of any Indebtedness of such Person or any of its Restricted
Subsidiaries and (b) any extraordinary or nonrecurring gain (or loss), together
with any related provision for taxes on such extraordinary or nonrecurring 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, without duplication,
(a) the direct costs relating to such Asset Sale (including, without limitation,
legal, accounting and investment banking fees, and sales commissions, recording
fees, title transfer fees and appraiser fees and cost of preparation of assets
for sale) and any relocation expenses incurred as a result thereof, (b) taxes
paid or payable as a result thereof (after taking into account any available tax
credits or deductions and any tax sharing arrangements), (c) amounts required to
be applied to the repayment of Indebtedness (other than revolving credit
Indebtedness incurred pursuant to the New Credit Facility) secured by a Lien on
the asset or assets that were the subject of such Asset Sale and (d) any reserve
established in accordance with GAAP or any amount placed in escrow, in either
case for adjustment in respect of the sale price of such asset or assets until
such time as such reserve is reversed or such escrow arrangement is terminated,
in which case Net Proceeds shall include only the amount of the reserve so
reversed or the amount returned to the Company or its Restricted Subsidiaries
from such escrow arrangement, as the case may be.

      "New Credit Facility" means that certain Credit Agreement, dated as of
October 11, 2000, among Advanstar Communications, Inc., as borrower, the various
financial institutions as are or may become parties thereto, DLJ Capital
Funding, Inc., as lead arranger and sole book runner and as syndication agent
and documentation agent, and Fleet National Bank, as administrative agent,
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, including
any agreement (i) extending or shortening the maturity of any Indebtedness
incurred thereunder or contemplated thereby, (ii) adding or deleting borrowers
or guarantors thereunder, (iii) increasing the amount of Indebtedness incurred
thereunder or available to be borrowed thereunder, provided that on the date
such Indebtedness is incurred it would not be prohibited by clause (i) of the
second paragraph of Section 4.09 hereof or (iv) otherwise altering the terms and
conditions thereof.

      "Non-Recourse Debt" means Indebtedness (i) 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

                                       11
<PAGE>

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
(ii) as to which the lenders have been notified in writing that they will not
have any recourse to the stock (other than the stock of an Unrestricted
Subsidiary pledged by the Company to secure debt of such Unrestricted
Subsidiary) or assets of the Company or any of its Restricted Subsidiaries;
provided that in no event shall Indebtedness of any Unrestricted Subsidiary fail
to be Non-Recourse Debt solely as a result of any default provisions contained
in a guarantee thereof by the Company or any of its Restricted Subsidiaries if
the Company or such Restricted Subsidiary was otherwise permitted to incur such
guarantee pursuant to this Indenture.

      "Non-U.S. Person" means a Person who is not a U.S. Person.

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

      "Notes" has the meaning set forth in the preamble to this Indenture.

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

      "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
Sections 10.04 and 10.05 hereof.

      "Opinion of Counsel" means an opinion from legal counsel who is reasonably
acceptable to the Trustee, that meets the requirements of Sections 10.04 and
10.05 hereof. The counsel may be an employee of or counsel to the Company, any
Subsidiary of the Company or the Trustee.

      "Pari Passu Indebtedness" means Indebtedness of the Company that ranks
pari passu in right of payment to the Notes.

      "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 The Depository Trust Company,
shall include Euroclear and Clearstream).

      "Permitted Business" means any Person engaged directly or indirectly in
the business-to-business marketing communications solutions business or any
business reasonably related, incidental or ancillary thereto.

                                       12
<PAGE>

      "Permitted Investments" means (a) any Investment in the Company or in a
Restricted Subsidiary of the Company, (b) any Investment in cash or Cash
Equivalents, (c) any Investment by the Company or any Restricted Subsidiary of
the Company in a Person, if as a result of such Investment (i) such Person
becomes a Restricted Subsidiary of the Company or (ii) 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 Wholly Owned
Restricted Subsidiary of the Company, (d) 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, (e) any Investment acquired solely
in exchange for Equity Interests (other than Disqualified Stock) of the Company,
(f) any Investment in a Person engaged in a Permitted Business (other than an
Investment in an Unrestricted Subsidiary) having an aggregate fair market value,
taken together with all other Investments made pursuant to this clause (f) that
are at that time outstanding, not to exceed 15% of Total Assets at the time of
such Investment (with the fair market value of each Investment being measured at
the time made and without giving effect to subsequent changes in value), (g)
Investments relating to any special purpose Wholly Owned Subsidiary of the
Company organized in connection with a Receivables Facility that, in the good
faith determination of the Board of Directors, are necessary or advisable to
effect such Receivables Facility, (h) the Management Loans or Investments in
Holdings to fund Management Loans, (i) Hedging Obligations permitted to be
incurred under Section 4.09 and (j) Investments made in any Subsidiary of the
Company that is principally engaged in a Permitted Business in connection with
the Internet which, together with all other Investments made pursuant to this
clause (j) since the Date of Issuance, does not exceed $30 million (in each
case, after giving effect to all subsequent reductions in the amount of any
Investment made pursuant to this clause (j) as a result of the repayment or
disposition thereof for cash, not to exceed the amount of the Investment
previously made pursuant to this clause (j)).

      "Permitted Liens" means: (i) Liens on property of a Person existing at the
time such Person is merged into or consolidated with the Company or any
Restricted Subsidiary; provided that such Liens were not incurred in
contemplation of such merger or consolidation and do not secure any property or
assets of the Company or any Restricted Subsidiary other than the property or
assets subject to the Liens prior to such merger or consolidation; (ii) Liens
existing on the Date of Issuance; (iii) Liens securing Indebtedness consisting
of Capitalized Lease Obligations, purchase money Indebtedness, mortgage
financings, industrial revenue bonds or other monetary obligations, in each case
incurred solely for the purpose of financing all or any part of the purchase
price or cost of construction or installation of assets used in the business of
the Company or its Restricted Subsidiaries, or repairs, additions or
improvements to such assets, provided that (A) such Liens secure Indebtedness in
an amount not in excess of the original purchase price or the original cost of
any such assets or repair, additional or improvement thereto (plus an amount
equal to the reasonable fees and expenses in connection with the incurrence of
such Indebtedness), (B) such Liens do not extend to any other assets of the
Company or its Restricted Subsidiaries (and, in the case of repair, addition or
improvements to any such assets, such Lien extends only to the assets (and
improvements thereto or thereon) repaired, added to or improved), (C) the
incurrence of such Indebtedness is permitted by Section 4.09 hereof and (D) such
Liens attach within 365 days of such purchase, construction, installation,
repair, addition or improvement; (iv) Liens to secure any refinancings,
renewals, extensions, modification or replacements

                                       13
<PAGE>

(collectively, "refinancings") (or successive refinancings), in whole or in
part, of any Indebtedness secured by Liens referred to in the clauses above so
long as such Lien does not extend to any other property (other than improvements
thereto); (v) Liens securing letters of credit entered into in the ordinary
course of business and consistent with past business practice; (vi) Liens on and
pledges of the capital stock of any Unrestricted Subsidiary securing
Non-Recourse Debt of such Unrestricted Subsidiary; (vii) Liens securing (A)
Indebtedness (including all Obligations) under the New Credit Facility or any
Foreign Credit Facility and (B) Hedging Obligations payable to a lender under
the New Credit Facility or an Affiliate thereof or to a Person that was a lender
or Affiliate thereof at the time the contract was entered into to the extent
such Hedging Obligations are secured by Liens on assets also securing
Indebtedness (including all Obligations) under the New Credit Facility; (viii)
Liens securing Indebtedness of any Restricted Subsidiary permitted to be
incurred by Section 4.09 and (ix) other Liens securing Indebtedness that is
permitted by the terms of this Indenture to be outstanding having an aggregate
principal amount at any one time outstanding not to exceed $25.0 million.

      "Permitted Refinancing Indebtedness" means any Indebtedness of the Company
or any of its Restricted Subsidiaries issued within 60 days after repayment of,
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 then classified as incurred pursuant to the Leverage
Ratio test in the first paragraph of or pursuant to clauses (ii), (iii), (iv),
(vi), (viii), (ix), (x) or (xii) of the second paragraph of Section 4.09;
provided that (a) the principal amount (or accreted value, if applicable) of
such Permitted Refinancing Indebtedness does not exceed the principal amount of
(or accreted value, if applicable), plus premium, if any, and accrued interest
on the Indebtedness so extended, refinanced, renewed, replaced, defeased or
refunded (plus the amount of reasonable expenses incurred in connection
therewith), (b) such Permitted Refinancing Indebtedness has a final maturity
date no 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, and (c) 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, taken as a whole, to the Holders of
Notes as those contained in the documentation governing the Indebtedness being
extended, refinanced, renewed, replaced, defeased or refunded; and provided
further, that if the Indebtedness being extended, refinanced, renewed, replaced,
defeased or refunded is Indebtedness of the Company, then such Permitted
Refinancing Indebtedness also must be Indebtedness of the Company.

      "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).

      "Principals" means DLJMB.

                                       14
<PAGE>

      "Private Placement Legend" means the legend set forth in Section
2.06(g)(i) to be placed on all Notes issued under this Indenture except where
otherwise permitted by the provisions of this Indenture.

      "QIB" means a "qualified institutional buyer" as defined in Rule 144A.

      "Qualified Proceeds" means any of the following or any combination of the
following: (i) cash; (ii) Cash Equivalents; (iii) assets (other than
Investments) that are used or useful in a Permitted Business; and (iv) the
Capital Stock of any Person engaged in a Permitted Business if, in connection
with the receipt by the Company or any Restricted Subsidiary of the Company of
such Capital Stock, (A) such Person becomes a Restricted Subsidiary of the
Company or any 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 any
Restricted Subsidiary of the Company.

      "Receivables Facility" means one or more receivables financing facilities,
as amended from time to time, pursuant to which the Company or any of its
Restricted Subsidiaries sells its accounts receivable to an Accounts Receivable
Subsidiary.

      "Receivables Fees" means distributions or payments made directly or by
means of discounts with respect to any participation interests issued or sold in
connection with, and other fees paid to a Person that is not a Restricted
Subsidiary in connection with, any Receivables Facility.

      "Registration Rights Agreement" means the Debt Registration Rights
Agreement, dated as of February 21, 2001, by and among the Company and the
purchasers listed on the signature pages thereto, as such agreement may be
amended, modified or supplemented from time to time.

      "Regulation S" means Regulation S promulgated under the Securities Act.

      "Regulation S Global Note" means a Regulation S Temporary Global Note or
Regulation S Permanent Global Note, as appropriate.

      "Regulation S Permanent Global Note" means a permanent global Note in the
form of Exhibit A-1 hereto bearing the Global Note Legend and the Private
Placement Legend, if applicable, and deposited with or on behalf of and
registered in the name of the Depositary or its nominee, issued in a
denomination equal to the outstanding principal amount of the Regulation S
Temporary Global Note upon expiration of the Restricted Period.

      "Regulation S Temporary Global Note" means a temporary global Note in the
form of Exhibit A-2 hereto bearing the Global Note Legend and the Private
Placement Legend and deposited with or on behalf of and registered in the name
of the Depositary or its nominee, issued in a denomination equal to the
outstanding principal amount of the Notes initially sold in reliance on Rule 903
of Regulation S which, for purposes of the Notes initially issued under this
Indenture, shall be zero.

                                       15
<PAGE>

      "Related Party" means, with respect to any Principal, (i) any controlling
stockholder or partner of such Principal on the Date of Issuance, or (ii) any
trust, corporation, partnership or other entity, the beneficiaries,
stockholders, partners, owners or Persons beneficially holding (directly or
through one or more Subsidiaries) a 51% or more controlling interest of which
consist of the Principals and/or such other Persons referred to in the
immediately preceding clauses (i) or (ii).

      "Responsible Officer," when used 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.

      "Restricted Definitive Note" means a Definitive Note bearing the Private
Placement Legend.

      "Restricted Global Note" means a Global Note bearing the Private Placement
Legend.

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

      "Restricted Period" means the 40-day distribution compliance period as
defined in Regulation S.

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

      "Rule 144" means Rule 144 promulgated under the Securities Act.

      "Rule 144A" means Rule 144A promulgated under the Securities Act.

      "Rule 903" means Rule 903 promulgated under the Securities Act.

      "Rule 904" means Rule 904 promulgated under the Securities Act.

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

      "Significant Subsidiary" means any Subsidiary that would be a "significant
subsidiary" as defined in Article 1, Rule 1-02 of Regulation S-X, promulgated
pursuant to the Securities Act, as such Regulation is in effect on the date
hereof.

      "Spot Rate" means, for any currency, the spot rate at which such currency
is offered for sale against United States dollars as determined by reference to
the New York foreign exchange selling rates, as published in The Wall Street
Journal on such date of determination for the immediately preceding business day
or, if such rate is not available, as determined in any publicly available
source of similar market data.

                                       16
<PAGE>

      "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.

      "Subsidiary" means, with respect to any Person, (a) any corporation,
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 (b) any partnership or limited liability company (i) the sole
general partner or the managing general partner or managing member of which is
such Person or a Subsidiary of such Person or (ii) the only general partners or
managing members of which are such Person or of one or more Subsidiaries of such
Person (or any combination thereof).

      "Tax Sharing Agreement" means any tax sharing agreement or arrangement
between the Company and Holdings, as the same may be amended from time to time;
provided that in no event shall the amount permitted to be paid pursuant to all
such agreements and/or arrangements exceed the amount the Company would be
required to pay for income taxes were it to file a consolidated tax return for
itself and its consolidated Restricted Subsidiaries as if it were a corporation
that was a parent of a consolidated group.

      "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 Assets" means the total consolidated assets of the Company and its
Restricted Subsidiaries, as shown on the most recent balance sheet (excluding
the footnotes thereto) of the Company.

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

      "Units" means the 171,792 units each consisting of $1,000 principal amount
at maturity of Notes and one Warrant.

      "Unrestricted Definitive Note" means one or more Definitive Notes that do
not bear and are not required to bear the Private Placement Legend.

      "Unrestricted Global Note" means a permanent global Note in the form of
Exhibit A-1 attached hereto that bears the Global Note Legend and that has the
"Schedule of Exchanges of Interests in the Global Note" attached thereto, and
that is deposited with or on behalf of and registered in the name of the
Depositary, representing a series of Notes that do not bear the Private
Placement Legend.

                                       17
<PAGE>

      "Unrestricted Subsidiary" means any Subsidiary that is designated by the
Board of Directors as an Unrestricted Subsidiary pursuant to a board resolution,
but only to the extent that such Subsidiary: (a) has no Indebtedness other than
Non-Recourse Debt; (b) 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
comply with Section 4.11; (c) is a Person with respect to which neither the
Company nor any of its Restricted Subsidiaries has any direct or indirect
obligation (i) to subscribe for additional Equity Interests (other than
Investments described in clause (g) of the definition of Permitted Investments)
or (ii) to maintain or preserve such Person's financial condition or to cause
such Person to achieve any specified levels, of operating results; and (d) has
not guaranteed or otherwise directly or indirectly provided credit support for
any Indebtedness of the Company or any of its Restricted Subsidiaries. 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 a Unrestricted Subsidiary, it shall thereafter cease
to be an Unrestricted Subsidiary for purposes of this Indenture and any
Indebtedness of such 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 such covenant). The Board of Directors may at any time
designate any Unrestricted Subsidiary to be a Restricted Subsidiary; provided
that such 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 such designation shall only be permitted if (i) such
Indebtedness is permitted under Section 4.09 hereof and (ii) no Default or Event
of Default would be in existence following such designation. Advanstar IH, Inc.
and its Subsidiaries shall be Unrestricted Subsidiaries until designated
otherwise by the Company pursuant to the preceding sentence.

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

      "Warrants" means the 171,792 warrants to purchase an aggregate of
1,441,545 shares of common stock (subject to adjustment) of Advanstar Holdings
Corp. initially issued as Units with the Notes. Each warrant will be exercisable
for 8.39122 shares of common stock (subject to adjustment) of Advanstar Holdings
Corp. initially at the exercise prices set forth therein.

      "Weighted Average Life to Maturity" means, when applied to any
Indebtedness at any date, the number of years obtained by dividing (a) the sum
of the products obtained by multiplying (i) 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 (ii) the
number of years (calculated to the nearest one-twelfth) that will elapse between
such date and the making of such payment, by (b) the then outstanding principal
amount of such Indebtedness.

                                       18
<PAGE>

      "Wholly Owned Restricted Subsidiary" of any Person means a Restricted
Subsidiary of such Person all 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.

      "Wholly Owned Subsidiary" of any Person means a 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 Subsidiaries of such Person.

      SECTION 1.02. Other Definitions.

                                                                     Defined in
                                Term                                   Section
"Affiliate Transaction" .......................................            4.11
"Asset Sale Offer" ............................................            4.10
"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
"Event of Default" ............................................            6.01
"Excess Proceeds" .............................................            4.10
"incur" .......................................................            4.09
"Legal Defeasance" ............................................            8.02
"Offer Amount" ................................................            3.09
"Offer Period" ................................................            3.09
"Paying Agent" ................................................            2.03
"Permitted Indebtedness" ......................................            4.09
"Purchase Date" ...............................................            3.09
"Registrar" ...................................................            2.03
"Restricted Payments" .........................................            4.07

      SECTION 1.03. Incorporation of TIA Provisions.

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

      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;

                                       19
<PAGE>

      "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 TIA reference to another statute or defined by Commission rule under
the TIA have the meanings so assigned to them.

      SECTION 1.04. Rules of Construction. Unless the context otherwise
requires:

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

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

            (3) "or" is not exclusive;

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

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

            (6) references to sections of or rules under the Securities Act
      shall be deemed to include substitute, replacement of successor sections
      or rules adopted by the Commission 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 principal amount
at maturity and integral multiples thereof.

      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-1 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-1 attached hereto (but

                                       20
<PAGE>

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 and redemptions.
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 Note Custodian, at the direction of
the Trustee, in accordance with instructions given by the Holder thereof as
required by Section 2.06 hereof.

      (c) Temporary Global Notes. Notes offered and sold in reliance on
Regulation S shall be issued initially in the form of Exhibit A-2 attached
hereto, which shall be deposited on behalf of the purchasers of the Notes
represented thereby with the Trustee, at its New York office, as custodian for
the Depositary, and registered in the name of the Depositary or the nominee of
the Depositary for the accounts of designated agents holding on behalf of
Euroclear or Clearstream, duly executed by the Company and authenticated by the
Trustee as hereinafter provided. The Restricted Period shall be terminated upon
the receipt by the Trustee of (i) a written certificate from the Depositary,
together with copies of certificates from Euroclear and Clearstream certifying
that they have received certification of non-United States beneficial ownership
of 100% of the aggregate principal amount of the Regulation S Temporary Global
Note (except to the extent of any beneficial owners thereof who acquired an
interest therein during the Restricted Period pursuant to another exemption from
registration under the Securities Act and who will take delivery of a beneficial
ownership interest in a 144A Global Note, all as contemplated by Section
2.06(a)(ii) hereof), and (ii) an Officers' Certificate from the Company.
Following the termination of the Restricted Period, beneficial interests in the
Regulation S Temporary Global Note shall be exchanged for beneficial interests
in Regulation S Permanent Global Notes pursuant to the Applicable Procedures.
Simultaneously with the authentication of Regulation S Permanent Global Notes,
the Trustee shall cancel the Regulation S Temporary Global Note. The aggregate
principal amount of the Regulation S Temporary Global Note and the Regulation S
Permanent Global Notes may from time to time be increased or decreased by
adjustments made on the records of the Trustee and the Depositary or its
nominee, as the case may be, in connection with transfers of interest as
hereinafter provided. Notwithstanding the foregoing, none of the Notes initially
issued under this Indenture shall be sold pursuant to Rule 903 of Regulation S
and the aggregate principal amount of the Regulation S Temporary Global Note
shall therefore at all times remain at zero.

      (d) 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 the Regulation S Temporary Global Note and
the Regulation S Permanent Global Notes that are held by Participants through
Euroclear or Clearstream.

                                       21
<PAGE>

      SECTION 2.02. Registrar and Paying Agent. One Officer shall sign the Notes
for the Company by manual or facsimile signature. The Company's seal may be
reproduced on the Notes and may be in facsimile form.

      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 one
Officer (an "Authentication Order"), authenticate Notes for original issue up to
the aggregate principal amount stated in paragraph 4 of the Notes. The aggregate
principal amount of Notes outstanding at any time may not exceed such amount
except as provided in Section 2.07 hereof.

      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 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 Note 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 Holders or the Trustee all
money held by the Paying Agent for the payment of principal, 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

                                       22
<PAGE>

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 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, 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 90 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) there shall have occurred and be continuing to occur a Default or Event of
Default with respect to the Notes; provided that in no event shall the
Regulation S Temporary Global Note be exchanged by the Company for Definitive
Notes prior to (x) the expiration of the Restricted Period and (y) the receipt
by the Registrar of any certificates required pursuant to Rule 903(c)(3)(ii)(B)
under the Securities Act. 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. In addition, beneficial interests in a
Global Note may be exchanged for certificated Notes upon request but only upon
at least 20 days' prior written notice given to the Trustee by or on behalf of
DTC in accordance with customary procedures. 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, except as provided in this Section 2.06. 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

                                       23
<PAGE>

Applicable Procedures. Beneficial interests in the Restricted Global Notes shall
be subject to restrictions on transfer comparable to those set forth herein to
the extent required by the Securities Act. 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 Restricted Global Note may be transferred to
      Persons who take delivery thereof in the form of a beneficial interest in
      the same Restricted Global Note in accordance with the transfer
      restrictions set forth in the Private Placement Legend; provided, however,
      that prior to the expiration of the Restricted Period, a beneficial
      interest in the Regulation S Global Note may be transferred to a person
      who takes delivery in the form of an interest in the corresponding 144A
      Global Note only upon receipt by the Trustee of a written certification
      from the transferor to the effect that such transfer is being made (i)(a)
      to a person whom the transferor reasonably believes is a QIB in a
      transaction meeting the requirements of Rule 144A or (b) pursuant to
      another exemption from the registration requirements under the Securities
      Act which is accompanied by an opinion of counsel regarding the
      availability of such exemption and (ii) in accordance with all applicable
      securities laws of any state of the United States or any other
      jurisdiction. Beneficial interests in any Unrestricted Global Note may be
      transferred to Persons who take delivery thereof in the form of a
      beneficial interest in an Unrestricted 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
      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; provided that in no event shall
      Definitive Notes be issued upon the transfer or exchange of beneficial
      interests in the Regulation S Temporary Global Note prior to (x) the
      expiration of the Restricted Period and (y) the receipt by the Registrar
      of any certificates required pursuant to Rule 903 under the Securities
      Act. 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

                                       24
<PAGE>

      Securities Act, the Trustee shall adjust the principal amount of the
      relevant Global Note(s) pursuant to Section 2.06(h) hereof.

            (iii) Transfer of Beneficial Interests to Another Restricted Global
      Note. A beneficial interest in any Restricted Global Note may be
      transferred to a Person who takes delivery thereof in the form of a
      beneficial interest in another Restricted Global Note if the transfer
      complies with the requirements of Section 2.06(b)(ii) above and the
      Registrar receives the following:

                  (A) if the transferee will take delivery in the form of a
            beneficial interest in the 144A Global Note, then the transferor
            must deliver a certificate in the form of Exhibit B hereto,
            including the certifications in item (1) thereof; and

                  (B) if the transferee will take delivery in the form of a
            beneficial interest in the Regulation S Temporary Global Note or the
            Regulation S Global Note, then the transferor must deliver a
            certificate in the form of Exhibit B hereto, including the
            certifications in item (2) thereof and, if the transfer occurs prior
            to the expiration of the Restricted Period, the interest transferred
            shall be held immediately thereafter through Euroclear or
            Clearstream.

            (iv) Transfer and Exchange of Beneficial Interests in a Restricted
      Global Note for Beneficial Interests in the Unrestricted Global Note. A
      beneficial interest in any Restricted Global Note may be exchanged by any
      holder thereof for a beneficial interest in an Unrestricted Global Note or
      transferred to a Person who takes delivery thereof in the form of a
      beneficial interest in an Unrestricted Global Note if the exchange or
      transfer complies with the requirements of Section 2.06(b)(ii) above and:

                  (A) such transfer is effected pursuant to a registration
            statement in accordance with the Registration Rights Agreement; or

                  (B) the Registrar receives the following:

                              (1) if the holder of such beneficial interest in a
                        Restricted Global Note proposes to exchange such
                        beneficial interest for a beneficial interest in an
                        Unrestricted Global Note, a certificate from such holder
                        in the form of Exhibit C hereto, including the
                        certifications in item (1)(a) thereof; or

                              (2) if the holder of such beneficial interest in a
                        Restricted Global Note proposes to transfer such
                        beneficial interest to a Person who shall take delivery
                        thereof in the form of a beneficial interest in an
                        Unrestricted Global Note, a certificate from such holder
                        in the form of Exhibit B hereto, including the
                        certifications in item (4) thereof,

                                       25
<PAGE>

            and, in each such case set forth in this subparagraph (B), if the
            Registrar so requests or if the Applicable Procedures so require, an
            Opinion of Counsel in form reasonably acceptable to the Registrar to
            the effect that such exchange or transfer is in compliance with the
            Securities Act and that the restrictions on transfer contained
            herein and in the Private Placement Legend are no longer required in
            order to maintain compliance with the Securities Act.

      If any such transfer is effected pursuant to subparagraph (A) or (B) above
at a time when an Unrestricted Global Note has not yet been issued, the Company
shall issue and, upon receipt of an Authentication Order in accordance with
Section 2.02 hereof, the Trustee shall authenticate one or more Unrestricted
Global Notes in an aggregate principal amount equal to the aggregate principal
amount of beneficial interests transferred pursuant to subparagraph (A) or (B)
above.

      Beneficial interests in an Unrestricted Global Note cannot be exchanged
for, or transferred to Persons who take delivery thereof in the form of, a
beneficial interest in a Restricted Global Note.

      (c) Transfer or Exchange of Beneficial Interests for Definitive Notes.

            (i) Beneficial Interests in Restricted Global Notes to Restricted
      Definitive Notes. If any holder of a beneficial interest in a Restricted
      Global Note proposes to exchange such beneficial interest for a Restricted
      Definitive Note or to transfer such beneficial interest to a Person who
      takes delivery thereof in the form of a Restricted Definitive Note, then,
      upon receipt by the Registrar of the following documentation:

                  (A) if the holder of such beneficial interest in a Restricted
            Global Note proposes to exchange such beneficial interest for a
            Restricted Definitive Note, a certificate from such holder in the
            form of Exhibit C hereto, including the certifications in item
            (2)(a) thereof;

                  (B) if such beneficial interest is being transferred to a QIB
            in accordance with Rule 144A under the Securities Act, a certificate
            to the effect set forth in Exhibit B hereto, including the
            certifications in item (1) thereof;

                  (C) if such beneficial interest is being transferred to a Non-
            U.S. Person in an offshore transaction in accordance with Rule 904
            under the Securities Act, a certificate to the effect set forth in
            Exhibit B hereto, including the certifications in item (2) thereof;

                  (D) if such beneficial interest is being transferred pursuant
            to an exemption from the registration requirements of the Securities
            Act in accordance with Rule 144 under the Securities Act, a
            certificate to the effect set forth in Exhibit B hereto, including
            the certifications in item (3)(a) thereof;

                                       26
<PAGE>

                  (E) if such beneficial interest is being transferred to an
            Institutional Accredited Investor in reliance on an exemption from
            the registration requirements of the Securities Act other than those
            listed in subparagraphs (B) through (D) above, a certificate to the
            effect set forth in Exhibit B hereto, including the certifications,
            certificates and Opinion of Counsel required by item (3) thereof, if
            applicable;

                  (F) if such beneficial interest is being transferred to the
            Company or any of its Subsidiaries, a certificate to the effect set
            forth in Exhibit B hereto, including the certifications in item
            (3)(b) thereof; or

                  (G) if such beneficial interest is being transferred pursuant
            to an effective registration statement under the Securities Act, a
            certificate to the effect set forth in Exhibit B hereto, including
            the certifications in item (3)(c) thereof,

      the Trustee shall cause the aggregate principal amount of the applicable
      Global Note to be reduced accordingly pursuant to Section 2.06(h) 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 in a Restricted Global Note pursuant to this
      Section 2.06(c) 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. The Trustee shall
      deliver such Definitive Notes to the Persons in whose names such Notes are
      so registered. Any Definitive Note issued in exchange for a beneficial
      interest in a Restricted Global Note pursuant to this Section 2.06(c)(i)
      shall bear the Private Placement Legend and shall be subject to all
      restrictions on transfer contained therein. In addition, any Definitive
      Note issued in exchange for a beneficial interest in a Restricted Global
      Note in an offshore transaction in accordance with Rule 904 under the
      Securities Act, shall bear the Private Placement Legend.

            (ii) Notwithstanding Sections 2.06(c)(i)(A) and (C) hereof, a
      beneficial interest in the Regulation S Temporary Global Note may not be
      exchanged for a Definitive Note or transferred to a Person who takes
      delivery thereof in the form of a Definitive Note prior to (x) the
      expiration of the Restricted Period and (y) the receipt by the Registrar
      of any certificates required pursuant to Rule 903(c)(3)(ii)(B) under the
      Securities Act, except in the case of a transfer pursuant to an exemption
      from the registration requirements of the Securities Act other than Rule
      903 or Rule 904.

            (iii) Beneficial Interests in Restricted Global Notes to
      Unrestricted Definitive Notes. A holder of a beneficial interest in a
      Restricted Global Note may exchange such beneficial interest for an
      Unrestricted Definitive Note or may transfer such beneficial interest to a
      Person who takes delivery thereof in the form of an Unrestricted
      Definitive Note only if:

                                       27
<PAGE>

                  (A) such transfer is effected pursuant to a registration
            statement in accordance with the Registration Rights Agreement; or

                  (B) the Registrar receives the following:

                              (1) if the holder of such beneficial interest in a
                        Restricted Global Note proposes to exchange such
                        beneficial interest for a Definitive Note that does not
                        bear the Private Placement Legend, a certificate from
                        such holder in the form of Exhibit C hereto, including
                        the certifications in item (1)(b) thereof; or

                              (2) if the holder of such beneficial interest in a
                        Restricted Global Note proposes to transfer such
                        beneficial interest to a Person who shall take delivery
                        thereof in the form of a Definitive Note that does not
                        bear the Private Placement Legend, a certificate from
                        such holder in the form of Exhibit B hereto, including
                        the certifications in item (4) thereof,

      and, in each such case set forth in this subparagraph (B), if the
      Registrar so requests or if the Applicable Procedures so require, an
      Opinion of Counsel in form reasonably acceptable to the Registrar to the
      effect that such exchange or transfer is in compliance with the Securities
      Act and that the restrictions on transfer contained herein and in the
      Private Placement Legend are no longer required in order to maintain
      compliance with the Securities Act.

            (iv) Beneficial Interests in Unrestricted Global Notes to
      Unrestricted Definitive Notes. If any holder of a beneficial interest in
      an Unrestricted 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 Section 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(h) 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)(iii) 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. The Trustee shall deliver such Definitive Notes to
      the Persons in whose names such Notes are so registered. Any Definitive
      Note issued in exchange for a beneficial interest pursuant to this Section
      2.06(c)(iii) shall not bear the Private Placement Legend.

      (d) Transfer and Exchange of Definitive Notes for Beneficial Interests.

            (i) Restricted Definitive Notes to Beneficial Interests in
      Restricted Global Notes. If any Holder of a Restricted Definitive Note
      proposes to exchange such Note for a beneficial interest in a Restricted
      Global Note or to

                                       28
<PAGE>

      transfer such Restricted Definitive Notes to a Person who takes delivery
      thereof in the form of a beneficial interest in a Restricted Global Note,
      then, upon receipt by the Registrar of the following documentation:

                  (A) if the Holder of such Restricted Definitive Note proposes
            to exchange such Note for a beneficial interest in a Restricted
            Global Note, a certificate from such Holder in the form of Exhibit C
            hereto, including the certifications in item (2)(b) thereof;

                  (B) if such Restricted Definitive Note is being transferred to
            a QIB in accordance with Rule 144A under the Securities Act, a
            certificate to the effect set forth in Exhibit B hereto, including
            the certifications in item (1) thereof;

                  (C) if such Restricted Definitive Note is being transferred to
            a Non-U.S. Person in an offshore transaction in accordance with Rule
            904 under the Securities Act, a certificate to the effect set forth
            in Exhibit B hereto, including the certifications in item (2)
            thereof;

                  (D) if such Restricted Definitive Note is being transferred
            pursuant to an exemption from the registration requirements of the
            Securities Act in accordance with Rule 144 under the Securities Act,
            a certificate to the effect set forth in Exhibit B hereto, including
            the certifications in item (3)(a) thereof;

                  (E) if such Restricted Definitive Note is being transferred to
            an Institutional Accredited Investor in reliance on an exemption
            from the registration requirements of the Securities Act other than
            those listed in subparagraphs (B) through (D) above, a certificate
            to the effect set forth in Exhibit B hereto, including the
            certifications, certificates and Opinion of Counsel required by item
            (3) thereof, if applicable;

                  (F) if such Restricted Definitive Note is being transferred to
            the Company or any of its Subsidiaries, a certificate to the effect
            set forth in Exhibit B hereto, including the certifications in item
            (3)(b) thereof; or

                  (G) if such Restricted Definitive Note is being transferred
            pursuant to an effective registration statement under the Securities
            Act, a certificate to the effect set forth in Exhibit B hereto,
            including the certifications in item (3)(c) thereof,

      the Trustee shall cancel the Restricted Definitive Note, increase or cause
      to be increased the aggregate principal amount of, in the case of clause
      (A) above, the appropriate Restricted Global Note, in the case of clause
      (B) above, the 144A Global Note, and in the case of clause (c) above, the
      Regulation S Global Note.

            (ii) Restricted Definitive Notes to Beneficial Interests in
      Unrestricted Global Notes. A Holder of a Restricted Definitive Note may
      exchange such

                                       29
<PAGE>

      Note for a beneficial interest in an Unrestricted Global Note or transfer
      such Restricted Definitive Note to a Person who takes delivery thereof in
      the form of a beneficial interest in an Unrestricted Global Note only if:

                  (A) such transfer is effected pursuant to a registration
            statement in accordance with the Registration Rights Agreement; or

                  (B) the Registrar receives the following:

                              (1) if the Holder of such Definitive Notes
                        proposes to exchange such Notes for a beneficial
                        interest in the Unrestricted Global Note, a certificate
                        from such Holder in the form of Exhibit C hereto,
                        including the certifications in item (1)(c) thereof; or

                              (2) if the Holder of such Definitive Notes
                        proposes to transfer such Notes to a Person who shall
                        take delivery thereof in the form of a beneficial
                        interest in the Unrestricted Global Note, a certificate
                        from such Holder in the form of Exhibit B hereto,
                        including the certifications in item (4) thereof,

            and, in each such case set forth in this subparagraph (B), if the
            Registrar so requests or if the Applicable Procedures so require, an
            Opinion of Counsel in form reasonably acceptable to the Registrar to
            the effect that such exchange or transfer is in compliance with the
            Securities Act and that the restrictions on transfer contained
            herein and in the Private Placement Legend are no longer required in
            order to maintain compliance with the Securities Act.

            Upon satisfaction of the conditions of any of the subparagraphs in
      this Section 2.06(d)(ii), the Trustee shall cancel the Definitive Notes
      and increase or cause to be increased the aggregate principal amount of
      the Unrestricted Global Note.

            (iii) Unrestricted Definitive Notes to Beneficial Interests in
      Unrestricted Global Notes. A Holder of an Unrestricted Definitive Note may
      exchange such Note for a beneficial interest in an Unrestricted Global
      Note or transfer such Definitive Notes to a Person who takes delivery
      thereof in the form of a beneficial interest in an Unrestricted Global
      Note at any time. Upon receipt of a request for such an exchange or
      transfer, the Trustee shall cancel the applicable Unrestricted Definitive
      Note and increase or cause to be increased the aggregate principal amount
      of one of the Unrestricted Global Notes.

      If any such exchange or transfer from a Definitive Note to a beneficial
interest is effected pursuant to subparagraphs (ii)(A), (ii)(B) or (iii) above
at a time when an Unrestricted Global Note has not yet been issued, the Company
shall issue and, upon receipt of an Authentication Order in accordance with
Section 2.02 hereof, the Trustee shall authenticate one or more Unrestricted
Global Notes in an aggregate principal amount equal to the principal amount of
Definitive Notes so transferred.

                                       30
<PAGE>

      (e) Transfer and Exchange of Definitive Notes for Definitive Notes. Upon
request by a Holder of Definitive Notes and such Holder's compliance with the
provisions of this Section 2.06(e), the Registrar shall register the transfer or
exchange of Definitive Notes. Prior to such registration of transfer or
exchange, the requesting Holder shall present or surrender 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 his attorney, duly authorized in writing. In addition, the requesting Holder
shall provide any additional certifications, documents and information, as
applicable, required pursuant to the following provisions of this Section
2.06(e).

      (i) Restricted Definitive Notes to Restricted Definitive Notes. Any
Restricted Definitive Note may be transferred to and registered in the name of
Persons who take delivery thereof in the form of a Restricted Definitive Note if
the Registrar receives the following:

            (A) if the transfer will be made pursuant to Rule 144A under the
      Securities Act, then the transferor must deliver a certificate in the form
      of Exhibit B hereto, including the certifications in item (1) thereof;

            (B) if the transfer will be made pursuant to Rule 904, then the
      transferor must deliver a certificate in the form of Exhibit B hereto,
      including the certifications in item (2) thereof; and

            (C) if the transfer will be made pursuant to any other exemption
      from the registration requirements of the Securities Act, then the
      transferor must deliver a certificate in the form of Exhibit B hereto,
      including the certifications, certificates and Opinion of Counsel required
      by item (3) thereof, if applicable.

         (ii) Restricted Definitive Notes to Unrestricted Definitive Notes. Any
Restricted Definitive Note may be exchanged by the Holder thereof for an
Unrestricted Definitive Note or transferred to a Person or Persons who take
delivery thereof in the form of an Unrestricted Definitive Note if:

            (A) any such transfer is effected pursuant to a registration
      statement in accordance with the Registration Rights Agreement; or

            (B) the Registrar receives the following:

                  (1) if the Holder of such Restricted Definitive Notes proposes
            to exchange such Notes for an Unrestricted Definitive Note, a
            certificate from such Holder in the form of Exhibit C hereto,
            including the certifications in item (1)(d) thereof; or

                  (2) if the Holder of such Restricted Definitive Notes proposes
            to transfer such Notes to a Person who shall take delivery thereof
            in the form of an Unrestricted Definitive Note, a certificate from
            such Holder in the form of Exhibit B hereto, including the
            certifications in item (4) thereof;

                                       31
<PAGE>

      and, in each such case set forth in this subparagraph (B), if the
      Registrar so requests, an Opinion of Counsel in form reasonably acceptable
      to the Company to the effect that such exchange or transfer is in
      compliance with the Securities Act and that the restrictions on transfer
      contained herein and in the Private Placement Legend are no longer
      required in order to maintain compliance with the Securities Act.

            (iii) Unrestricted Definitive Notes to Unrestricted Definitive
      Notes. A Holder of Unrestricted Definitive Notes may transfer such Notes
      to a Person who takes delivery thereof in the form of an Unrestricted
      Definitive Note. Upon receipt of a request to register such a transfer,
      the Registrar shall register the Unrestricted Definitive Notes pursuant to
      the instructions from the Holder thereof.

      (f) [RESERVED]

      (g) Legends. The following legends shall appear on the face of all Global
Notes and Definitive Notes issued under this Indenture unless specifically
stated otherwise in the applicable provisions of this Indenture.

            (i) Private Placement Legend.

                  (A) Except as permitted by subparagraph (B) below, each Global
            Note and each Definitive Note (and all Notes issued in exchange
            therefor or substitution thereof) shall bear the legend in
            substantially the following form:

                  "THIS NOTE (OR ITS PREDECESSOR) HAS NOT BEEN REGISTERED UNDER
                  THE U.S. SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES
                  ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED, SOLD, PLEDGED OR
                  OTHERWISE TRANSFERRED WITHIN THE UNITED STATES OR TO, OR FOR
                  THE ACCOUNT OR BENEFIT OF, U.S. PERSONS, EXCEPT AS SET FORTH
                  IN THE NEXT SENTENCE. BY ITS ACQUISITION HEREOF OR OF A
                  BENEFICIAL INTEREST HEREIN, THE HOLDER: (1) REPRESENTS THAT
                  (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN
                  RULE 144A UNDER THE SECURITIES ACT) (A "QIB"), (B) IT HAS
                  ACQUIRED THIS NOTE IN AN OFFSHORE TRANSACTION IN COMPLIANCE
                  WITH REGULATION S UNDER THE SECURITIES ACT OR (C) IT IS AN
                  INSTITUTIONAL "ACCREDITED INVESTOR" (AS DEFINED IN RULE
                  501(A)(1), (2), (3) OR (7) OF REGULATION D UNDER THE
                  SECURITIES ACT (AN "IAI")), (2) AGREES THAT IT WILL NOT RESELL
                  OR OTHERWISE TRANSFER THIS NOTE EXCEPT (A) TO THE COMPANY OR
                  ANY OF ITS SUBSIDIARIES, (B) TO A PERSON WHOM THE SELLER

                                       32
<PAGE>

                  REASONABLY BELIEVES IS A QIB PURCHASING FOR ITS OWN ACCOUNT OR
                  FOR THE ACCOUNT OF A QIB IN A TRANSACTION MEETING THE
                  REQUIREMENTS OF RULE 144A, (C) IN AN OFFSHORE TRANSACTION
                  MEETING THE REQUIREMENTS OF 904 OF THE SECURITIES ACT, (D) IN
                  A TRANSACTION MEETING THE REQUIREMENTS OF RULE 144 UNDER THE
                  SECURITIES ACT, (E) TO AN IAI THAT, PRIOR TO SUCH TRANSFER,
                  FURNISHES THE TRUSTEE A SIGNED LETTER CONTAINING CERTAIN
                  REPRESENTATIONS AND AGREEMENTS RELATING TO THE TRANSFER OF
                  THIS NOTE (THE FORM OF WHICH CAN BE OBTAINED FROM THE TRUSTEE)
                  AND, IF SUCH TRANSFER IS IN RESPECT OF NOTES WITH AN ACCRETED
                  VALUE OF LESS THAN $250,000, AN OPINION OF COUNSEL ACCEPTABLE
                  TO THE COMPANY THAT SUCH TRANSFER IS IN COMPLIANCE WITH THE
                  SECURITIES ACT, (F) IN ACCORDANCE WITH ANOTHER EXEMPTION FROM
                  THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT (AND BASED
                  UPON AN OPINION OF COUNSEL ACCEPTABLE TO THE COMPANY) OR (G)
                  PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT AND, IN EACH
                  CASE, IN ACCORDANCE WITH THE APPLICABLE SECURITIES LAWS OF ANY
                  STATE OF THE UNITED STATES OR ANY OTHER APPLICABLE
                  JURISDICTION AND (3) AGREES THAT IT WILL DELIVER TO EACH
                  PERSON TO WHOM THIS NOTE OR AN INTEREST HEREIN IS TRANSFERRED
                  A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. AS USED
                  HEREIN, THE TERMS "OFFSHORE TRANSACTION" AND "UNITED STATES"
                  HAVE THE MEANINGS GIVEN TO THEM BY RULE 902 OF REGULATION S
                  UNDER THE SECURITIES ACT. THE INDENTURE CONTAINS A PROVISION
                  REQUIRING THE TRUSTEE TO REFUSE TO REGISTER ANY TRANSFER OF
                  THIS NOTE IN VIOLATION OF THE FOREGOING."

                  (B) Notwithstanding the foregoing, any Global Note or
            Definitive Note issued pursuant to subparagraphs (b)(iv), (c)(iii),
            c(iv), (d)(ii), (d)(iii), (e)(ii) or (e)(iii) of this Section 2.06
            (and all Notes issued in exchange therefor or substitution thereof)
            shall not bear the Private Placement Legend.

            (ii) Global Note Legend. 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

                                       33
<PAGE>

                  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 2.07 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
                  ADVANSTAR, INC."

            (iii) Regulation S Temporary Global Note Legend. The Regulation S
      Temporary Global Note shall bear a legend in substantially the following
      form:

                  "THE RIGHTS ATTACHING TO THIS REGULATION S TEMPORARY GLOBAL
                  NOTE, AND THE CONDITIONS AND PROCEDURES GOVERNING ITS EXCHANGE
                  FOR CERTIFICATED NOTES, ARE AS SPECIFIED IN THE INDENTURE (AS
                  DEFINED HEREIN). NEITHER THE HOLDER NOR THE BENEFICIAL OWNERS
                  OF THIS REGULATION S TEMPORARY GLOBAL NOTE SHALL BE ENTITLED
                  TO RECEIVE PAYMENT OF INTEREST HEREON."

      (h) 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
cancelled in whole and not in part, each such Global Note shall be returned to
or retained and cancelled 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 at maturity 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 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.

      (i) 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.

                                       34
<PAGE>

            (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 3.06, 3.09, 4.10 and 4.14 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 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.

            (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

                                       35
<PAGE>

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 cancelled 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 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 at maturity 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.

      SECTION 2.09. Treasury Notes. In determining whether the Holders of the
required principal amount at maturity 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.

                                       36
<PAGE>

      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 destroy cancelled Notes (subject to the record retention requirement of
the Exchange Act). Certification of the destruction of all cancelled Notes shall
be delivered to the Company. The Company may not issue new Notes to replace
Notes that it has paid or that have been delivered to the Trustee for
cancellation.

      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.

                                    ARTICLE 3
                            REDEMPTION AND PREPAYMENT

      SECTION 3.01. Notices to Trustees. 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 (i) the clause of this
Indenture pursuant to which the redemption shall occur, (ii) the redemption
date, (iii) the principal amount at maturity of Notes to be redeemed and (iv)
the redemption price.

      SECTION 3.02. Selection of Notes to Be Redeemed. If less than all of the
Notes are to be redeemed at any time, selection of Notes for redemption will be
made by the Trustee in compliance with the requirements of the principal
national securities exchange, if any, on which the Notes are listed, or, if the
Notes are not so listed, on a pro rata basis, by lot or by such method as the
Trustee shall deem fair and appropriate; provided that no Notes of $1,000
principal amount at maturity or less shall be redeemed in part.

      The Trustee shall promptly notify the Company in writing of the Notes
selected for redemption and, in the case of any Note selected for partial
redemption, the principal amount at maturity thereof to be redeemed. Notes and
portions of Notes selected shall be in amounts of $1,000 principal amount at
maturity or whole multiples of $1,000; except that if all of the Notes of a
Holder are to be redeemed, the entire outstanding

                                       37
<PAGE>

principal amount at maturity of Notes held by such Holder, even if not a
multiple of $1,000, shall be redeemed. 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.

      SECTION 3.03. Notice of Redemption. Subject to the provisions of Section
3.09 hereof, notices of redemption shall be mailed by first class mail at least
30 but not more than 60 days before the redemption date to each Holder of Notes
to be redeemed at its registered address. If any Note is to be redeemed in part
only, the notice of redemption that relates to such Note shall state the portion
of the principal amount at maturity thereof to be redeemed. A new Note in
principal amount at maturity equal to the unredeemed portion thereof will be
issued in the name of the Holder thereof upon cancellation of the original Note.
Notes called for redemption become due on the date fixed for redemption. On and
after the redemption date, interest ceases to accrue on Notes or portions of
Notes called for redemption.

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

      (a) the redemption date;

      (b) the redemption price;

      (c) if any Note is being redeemed in part, the portion of the principal
amount at maturity 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 at
maturity equal to the unredeemed portion shall be issued upon cancellation of
the original Note;

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

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

      (f) 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;

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

      (h) 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.

                                       38
<PAGE>

      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. A notice of redemption may not be conditional.

      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 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 at maturity to the unredeemed
portion of the Note surrendered.

      SECTION 3.07. Optional Redemption. (a) The Notes will be subject to
redemption at any time at the option of the Company, in whole or in part, upon
not less than 30 nor more than 60 days' notice, in cash at the redemption prices
(expressed as percentages of Accreted Value) equal to 115.000%, if redeemed at
any time from the Date of Issuance until October 15, 2005, and at the redemption
prices set forth below, plus accrued and unpaid interest, if any, thereon to the
applicable redemption date, if redeemed during the twelve-month period beginning
on October 15 of the years indicated below:

                            Year                         Percentage

                    2005 .......................          107.500%
                    2006 .......................          103.750%
                    2007 .......................          101.875%
                    2008 and thereafter ........          100.000%

                                       39
<PAGE>

      (b) any redemption pursuant to this Section 3.07 shall be made pursuant to
the provisions of Sections 3.01 through 3.06 hereof.

      SECTION 3.08. Mandatory Redemption. The Company is not required to make
mandatory redemption of, 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 Asset Sale Offer (as defined in Section 4.10 hereof), 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 principal amount at maturity of Notes required to
be purchased pursuant to Section 4.10 hereof (the "Offer Amount") or, if less
than the Offer Amount has been tendered, all Notes tendered in response to the
Asset 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:

            (a) 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;

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

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

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

            (e) that Holders electing to have a Note purchased pursuant to an
      Asset Sale Offer may only elect to have all of such Note purchased and may
      not elect to have only a portion of such Note purchased;

                                       40
<PAGE>

            (f) 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;

            (g) 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;

            (h) that, if the aggregate principal amount at maturity of Notes
      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

            (i) that Holders whose Notes were purchased only in part shall be
      issued new Notes equal in principal amount at maturity 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 tendered, and
shall deliver to the Trustee an Officers' Certificate stating that such 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 at maturity 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.

                                       41
<PAGE>

                                    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.

      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; and 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 agent 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 rules and
regulations of the Commission, so long as any Notes are outstanding, the Company
will furnish to the Holders of Notes (a) all quarterly and annual financial
information that would be required to be contained in a filing with the
Commission 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" and, with respect to the annual information only, a
report thereon by the Company's certified independent accountants, and (b) all
current reports that would be required to be filed with the

                                       42
<PAGE>

Commission on Form 8-K if the Company were required to file such reports, in
each case, within the time periods specified in the Commission's rules and
regulations. In addition, following the declaration of effectiveness of a
registration statement filed pursuant to the terms of the Registration Rights
Agreement, whether or not required by the rules and regulations of the
Commission, the Company will file a copy of all such information and reports
with the Commission for public availability within the time periods specified in
the Commission's rules and regulations (unless the Commission will not accept
such a filing) and make such information available to securities analysts and
prospective investors upon request. In addition, the Company agrees that, for so
long as any Notes remain outstanding, they will furnish to the Holders and to
securities analysts and prospective investors, upon their request, the
information required to be delivered pursuant to Rule 144A(d)(4) under the
Securities Act.

      SECTION 4.04. Compliance Certificate. (a) 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 have been made under the
supervision of the signing Officers with a view to determining whether the
Company have 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
propose to take with respect thereto) and that to the best of his or her
knowledge no event has occurred and remains in existence by reason of which
payments on account of the principal of or interest on the Notes is prohibited
or if such event has occurred, a description of the event and what action the
Company is taking or proposes to take with respect thereto.

      (b) So long as not contrary to the then current recommendations of the
American Institute of Certified Public Accountants, the year-end financial
statements delivered pursuant to Section 4.03(a) above shall be accompanied by a
written statement of the Company's independent public accountants (which shall
be a firm of established national reputation) that in making the examination
necessary for certification of such financial statements, nothing has come to
their attention that would lead them to believe that the Company has violated
any provisions of Article 4 or Article 5 hereof or, if any such violation has
occurred, specifying the nature and period of existence thereof, it being
understood that such accountants shall not be liable directly or indirectly to
any Person for any failure to obtain knowledge of any such violation.

      (c) 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.

      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

                                       43
<PAGE>

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 that
(to the extent permitted by law) 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 hereby expressly waives (to the extent permitted by law) all benefit or
advantage of any such law, and covenants that (to the extent permitted by law)
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, (a)
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 (other
than dividends or distributions payable in Equity Interests (other than
Disqualified Stock) of the Company or dividends or distributions payable to the
Company or any Restricted Subsidiary of the Company); (b) purchase, redeem or
otherwise acquire or retire for value any Equity Interests of the Company or
Holdings (other than any such Equity Interests owned by the Company or any
Restricted Subsidiary of the Company); (c) make any principal payment on or with
respect to, or purchase, redeem, defease or otherwise acquire or retire for
value, any Indebtedness of the Company that is subordinated in right of payment
to the Notes, except in accordance with the mandatory redemption or repayment
provisions set forth in the original documentation governing such Indebtedness
(but not pursuant to any mandatory offer to repurchase upon the occurrence of
any event); or (d) make any Restricted Investment (all such payments and other
actions set forth in clauses (a) through (d) above being collectively referred
to as "Restricted Payments"), unless, at the time of and after giving effect to
such Restricted Payment:

            (i) no Default or Event of Default shall have occurred and be
      continuing or would occur as a consequence thereof; and

            (ii) the Company would, immediately after giving pro forma effect
      thereto as if such Restricted Payment had been made at the beginning of
      the applicable four-quarter period, have been permitted to incur at least
      $1.00 of additional Indebtedness pursuant to the Leverage Ratio test set
      forth in the first paragraph of Section 4.09 hereof; and

            (iii) such Restricted Payment, together with the aggregate amount of
      all other Restricted Payments made by the Company and its Restricted
      Subsidiaries after the Date of Issuance (excluding Restricted Payments
      permitted by clauses (a) (to the extent that the declaration of any
      dividend referred to therein reduces amounts available for Restricted
      Payments pursuant to this clause (iii)), (b) through (i), (k), (l), (n),
      (o), (p) and (r) of the next succeeding paragraph), is less than the sum,
      without duplication, of

                                       44
<PAGE>

            (A)   (i) the aggregate amount of Consolidated Cash Flow (or, if
                  Consolidated Cash Flow is negative, 100% of such negative
                  amount) accrued on a cumulative basis during the period (taken
                  as one accounting period) beginning on January 1, 2001 and
                  ending on the last day of the most recent fiscal quarter for
                  which internal financial statements are available less (ii)
                  150% of Consolidated Interest Expense of the Company accrued
                  on a cumulative basis for such period, plus

            (B)   100% of the Qualified Proceeds received by the Company after
                  the Date of Issuance from (less any such Qualified Proceeds
                  used to make any Investment contemplated by clause (q) below)
                  contributions to the Company's capital or from the issue or
                  sale on or after the Date of Issuance of Equity Interests of
                  the Company or of Disqualified Stock or convertible debt
                  securities of the Company to the extent that they have been
                  converted into such Equity Interests (other than Equity
                  Interests, Disqualified Stock or convertible debt securities
                  sold to a Subsidiary of the Company and other than
                  Disqualified Stock or convertible debt securities that have
                  been converted into Disqualified Stock), plus

            (C)   the amount equal to the net reduction in Investments in
                  Persons after the Date of Issuance who are not Restricted
                  Subsidiaries (other than Permitted Investments) resulting from
                  (x) Qualified Proceeds received as a dividend, repayment of a
                  loan or advance or other transfer of assets (valued at the
                  fair market value thereof) to the Company or any Restricted
                  Subsidiary from such Persons, (y) Qualified Proceeds received
                  upon the sale or liquidation of such Investments and (z) the
                  redesignation of Unrestricted Subsidiaries (excluding any
                  increase in the amount available for Restricted Payments
                  pursuant to clause (j) or (n) below arising from the
                  redesignation of such Unrestricted Subsidiary) whose assets
                  are used or useful in, or which is engaged in, one or more
                  Permitted Business as Restricted Subsidiaries (valued
                  (proportionate to the Company's equity interest in such
                  Subsidiary at the time of such redesignation) at the fair
                  market value of the net assets of such Subsidiary at the time
                  of such redesignation).

      The foregoing provisions will not prohibit:

      (a) the payment of any dividend within 60 days after the date of
declaration thereof, if at said date of declaration such payment would have
complied with the provisions of this Indenture;

      (b) the redemption, repurchase, retirement, defeasance or other
acquisition of any subordinated Indebtedness or Equity Interests of the Company
(the "Retired Capital Stock") in exchange for, or out of the net cash proceeds
of the substantially concurrent

                                       45
<PAGE>

sale (other than to a Subsidiary of the Company) of, other Equity Interests of
the Company (other than any Disqualified Stock) (the "Refunding Capital Stock");
provided that the amount of any such net cash proceeds that are utilized for any
such redemption, repurchase, retirement, defeasance or other acquisition shall
be excluded from clause (iii)(B) of the preceding paragraph;

      (c) the defeasance, redemption, repurchase, retirement or other
acquisition of subordinated Indebtedness of the Company with the net cash
proceeds from an incurrence of, or in exchange for, Permitted Refinancing
Indebtedness;

      (d) the repurchase, redemption or other acquisition or retirement for
value of any Equity Interests of the Company or Holdings held by any member of
the Company's (or any of its Restricted Subsidiaries') management pursuant to
any management equity subscription agreement or stock option agreement and any
dividend to Holdings to fund any such repurchase, redemption, acquisition or
retirement, provided that the aggregate price paid for all such repurchased,
redeemed, acquired or retired Equity Interests shall not exceed (x) $7.5 million
in any calendar year (with unused amounts in any calendar year being carried
over to succeeding calendar years subject to a maximum (without giving effect to
the following clause (y)) of $15.0 million in any calendar year), plus (y) the
aggregate cash proceeds received by the Company during such calendar year from
any reissuance of Equity Interests by the Company or Holdings to members of
management of the Company and its Restricted Subsidiaries and (ii) no Default or
Event of Default shall have occurred and be continuing immediately after such
transaction;

      (e) payments and transactions in connection with the Acquisition including
any purchase price adjustment or any other payments made pursuant to the
Acquisition Agreement or the financial advisory agreements with Credit Suisse
First Boston Corporation, the Acquisition Financing, the New Credit Facility
(including commitment, syndication and arrangement fees payable thereunder) and
the application of the proceeds thereof, and the payment of fees and expenses
with respect thereto;

      (f) the payment of dividends or the making of loans or advances by the
Company to Holdings to pay for expenses incurred by Holdings in its capacity as
a holding company or for services rendered by Holdings on behalf of the Company
(including advisory fees in an amount not to exceed $1.0 million in the
aggregate in any Fiscal Year) in an amount not to exceed $5.0 million in the
aggregate in any Fiscal Year;

      (g) payments or distributions to Holdings pursuant to any Tax Sharing
Agreement;

      (h) the payment of dividends by a Restricted Subsidiary on any class of
common stock of such Restricted Subsidiary if (i) such dividend is paid pro rata
to all holders of such class of common stock and (ii) at least 51% of such class
of common stock is held by the Company or one or more of its Restricted
Subsidiaries;

      (i) the repurchase of any class of common stock of a Restricted Subsidiary
if (i) such repurchase is made pro rata with respect to such class of common
stock and (ii) at least 51% of such class of common stock is held by the Company
or one or more of its Restricted Subsidiaries;

                                       46
<PAGE>

      (j) any other Restricted Investment made in a Permitted Business which,
together with all other Restricted Investments made pursuant to this clause (j)
since the Date of Issuance, does not exceed $30.0 million (in each case, after
giving effect to all subsequent reductions in the amount of any Restricted
Investment made pursuant to this clause (j), either as a result of (i) the
repayment or disposition thereof for cash or (ii) the redesignation of an
Unrestricted Subsidiary as a Restricted Subsidiary valued (proportionate to the
Company's equity interest in such Subsidiary at the time of such redesignation)
at the fair market value of the net assets of such Subsidiary at the time of
such redesignation, in the case of clause (i) and (ii), not to exceed the amount
of the Restricted Investment previously made pursuant to this clause (j);
provided that no Default or Event of Default shall have occurred and be
continuing immediately after making such Restricted Investment;

      (k) the declaration and payment of dividends to holders of any class or
series of Disqualified Stock of the Company or any Restricted Subsidiary issued
on or after the Date of Issuance in accordance with Section 4.09 hereof;
provided that no Default or Event of Default shall have occurred and be
continuing immediately after making such Restricted Payment;

      (l) repurchases of Equity Interests deemed to occur upon exercise of stock
options if such Equity Interests represent a portion of the exercise price of
such options;

      (m) the payment of dividends or distributions on the Company's common
stock, following the first public offering of the Company's common stock or
Holdings' common stock after the Date of Issuance, of up to 6.0% per annum of
(i) the net proceeds received by the Company from such public offering of its
common stock or (ii) the net proceeds received by the Company from such public
offering of Holdings' common stock as common equity or preferred equity (other
than Disqualified Stock), other than, in each case, with respect to public
offerings with respect to the Company's common stock or Holdings' common stock
registered on Form S-8; provided that no Default or Event of Default shall have
occurred and be continuing immediately after any such payment of dividends or
distributions;

      (n) any other Restricted Payment which, together with all other Restricted
Payments made pursuant to this clause (n) since the Date of Issuance, does not
exceed $30.0 million (in each case, after giving effect to all subsequent
reductions in the amount of any Restricted Investment made pursuant to this
clause (n) either as a result of (i) the repayment or disposition thereof for
cash or (ii) the redesignation of an Unrestricted Subsidiary as a Restricted
Subsidiary valued (proportionate to the Company's equity interest in such
Subsidiary at the time of such redesignation) at the fair market value of the
net assets of such Subsidiary at the time of such redesignation, in the case of
clauses (i) and (ii), not to exceed the amount of the Restricted Investment
previously made pursuant to this clause (n); provided that no Default or Event
of Default shall have occurred and be continuing immediately after making such
Restricted Payment;

      (o) the pledge by the Company of the Capital Stock of an Unrestricted
Subsidiary of the Company to secure Non-Recourse Debt of such Unrestricted
Subsidiary;

                                       47
<PAGE>

      (p) the purchase, redemption or other acquisition or retirement for value
of any Equity Interests of any Restricted Subsidiary issued after the Date of
Issuance, provided that the aggregate price paid for any such repurchased,
redeemed, acquired or retired Equity Interests shall not exceed the sum of (i)
the amount of cash and Cash Equivalents received by such Restricted Subsidiary
from the issue or sale thereof and (ii) any accrued dividends thereon the
payment of which would be permitted pursuant to clause (k) above;

      (q) any Investment in an Unrestricted Subsidiary that is funded by
Qualified Proceeds received by the Company on or after the Date of Issuance from
contributions to the Company's capital or from the issue and sale on or after
the Date of Issuance of Equity Interests of the Company or of Disqualified Stock
or convertible debt securities to the extent they have been converted into such
Equity Interests (other than Equity Interests, Disqualified Stock or convertible
debt securities sold to a Subsidiary of the Company and other than Disqualified
Stock or convertible debt securities that have been converted into Disqualified
Stock) in an amount (measured at the time such Investment is made and without
giving effect to subsequent changes in value) that does not exceed the amount of
such Qualified Proceeds (excluding any such Qualified Proceeds to the extent
utilized to permit a prior "Restricted Payment" pursuant to clause (iii)(B) of
the preceding paragraph); and

      (r) distributions or payments of Receivables Fees.

      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 designation, 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
such designation and will reduce the amount available for Restricted Payments
under the first paragraph of this Section 4.07; provided that no adjustment
shall be required for the Subsidiaries designated as Unrestricted Subsidiaries
on the Date of Issuance pursuant to the definition thereof. All such outstanding
Investments will be deemed to constitute Restricted Investments in an amount
equal to the greater of (i) the net book value of such Investments at the time
of such designation and (ii) the fair market value of such Investments at the
time of such designation. Such designation will only be permitted if such
Restricted Investment would be permitted at such time and if such Restricted
Subsidiary otherwise meets the definition of an Unrestricted Subsidiary.

      The amount of (i) all Restricted Payments (other than cash) shall be the
fair market value on the date of the Restricted Payment of the asset(s) or
securities proposed to be transferred or issued by the Company or such
Restricted Subsidiary, as the case may be, pursuant to the Restricted Payment
and (ii) Qualified Proceeds (other than cash) shall be the fair market value on
the date of receipt thereof by the Company of such Qualified Proceeds. The fair
market value of any non-cash Restricted Payment shall be determined by the Board
of Directors whose resolution with respect thereto shall be delivered to the
Trustee.

                                       48
<PAGE>

      Not later than the date of making any Restricted Payment, the Company
shall deliver to the Trustee an Officers' Certificate stating that such
Restricted Payment is permitted and setting forth the basis upon which the
calculations required by this Section 4.07 were computed.

      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 (a)(i) pay dividends or make any other distributions to
the Company or any of its Restricted Subsidiaries (A) on its Capital Stock or
(B) with respect to any other interest or participation in, or measured by, its
profits, or (ii) pay any Indebtedness owed to the Company or any of its
Restricted Subsidiaries, (b) make loans or advances to the Company or any of its
Restricted Subsidiaries or (c) transfer any of its properties or assets to the
Company or any of its Restricted Subsidiaries. However, the foregoing
restrictions will not apply to encumbrances or restrictions existing under or by
reason of (a) Existing Indebtedness as in effect on the Date of Issuance, (b)
the New Credit Facility as in effect as of the Date of Issuance, and any
amendments, modifications, restatements, renewals, increases, supplements,
refundings, replacements or refinancings thereof, provided that the encumbrances
or restrictions imposed thereby are, in the good faith judgment of the Board of
Directors, not materially less favorable, taken as a whole, to the Holders of
the Notes than those contained in the New Credit Facility as in effect as of the
Date of Issuance, (c) this Indenture and the Notes, (d) applicable law and any
applicable rule, regulation or order, (e) any agreement or instrument of a
Person acquired by the Company or any of its Restricted Subsidiaries as in
effect at the time of such acquisition (except to the extent created in
contemplation of such 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, provided that,
in the case of Indebtedness, such Indebtedness was permitted by the terms of
this Indenture to be incurred, (f) customary non-assignment provisions in leases
entered into in the ordinary course of business and consistent with past
practices, (g) purchase money obligations for property acquired in the ordinary
course of business that impose restrictions of the nature described in clause
(e) above on the property so acquired, (h) contracts for the sale of assets,
including, without limitation, customary restrictions with respect to a
Subsidiary pursuant to an agreement that has been entered into for the sale or
disposition of all or substantially all of the Capital Stock or assets of such
Subsidiary, (i) Permitted Refinancing Indebtedness, provided that the
restrictions contained in the agreements governing such Permitted Refinancing
Indebtedness are, in the good faith judgment of the Board of Directors, not
materially less favorable, taken as a whole, to the Holders of the Notes than
those contained in the agreements governing the Indebtedness being refinanced,
(j) secured Indebtedness otherwise permitted to be incurred pursuant to Sections
4.09 and 4.12 hereof that limit the right of the debtor to dispose of the assets
securing such Indebtedness, (k) restrictions on cash or other deposits or net
worth imposed by customers under contracts entered into in the ordinary course
of business, (l) other Indebtedness or Disqualified Stock of Restricted
Subsidiaries permitted to be incurred subsequent to the Date of Issuance
pursuant to the provisions of Section 4.09 hereof, provided that the
encumbrances or restrictions imposed thereby are, in the good faith judgment of
the Board of Directors, not materially less favorable, taken as a whole, to the
Holders of the Notes than those contained in any

                                       49
<PAGE>

agreement governing any Indebtedness or Disqualified Stock of such Restricted
Subsidiary existing on the Date of Issuance, (m) customary provisions in joint
venture agreements and other similar agreements entered into in the ordinary
course of business, and (n) restrictions created in connection with any
Receivables Facility that, in the good faith determination of the Board of
Directors, are necessary or advisable to effect such Receivables Facility.

      SECTION 4.09. Incurrence of Indebtedness and Issuance of Preferred Stock.
(a) 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
Indebtedness), (b) the Company will not, and will not permit any of its
Restricted Subsidiaries to, issue any shares of Disqualified Stock and (c) the
Company will not permit any of its Restricted Subsidiaries to issue any shares
of preferred stock; provided that the Company or any Restricted Subsidiary may
incur Indebtedness (including Acquired Indebtedness) or issue shares of
Disqualified Stock if the Leverage Ratio for the Company's most recently ended
four full fiscal quarters for which internal financial statements are available
immediately preceding the date on which such additional Indebtedness is incurred
or such Disqualified Stock is issued would have been no greater than 6.5 to 1 if
such four-quarter period ended on or prior to December 31, 2002 and 6.25 to 1
thereafter but, in each case, not less than 0, determined on a consolidated pro
forma basis (including a pro forma application of the net proceeds therefrom),
as if the additional Indebtedness had been incurred, or the Disqualified Stock
had been issued, as the case may be, at the beginning of such four- quarter
period.

      The provisions of the first paragraph of this Section 4.09 will not apply
to the incurrence of any of the following items of Indebtedness (collectively,
"Permitted Indebtedness"):

            (i) Indebtedness of the Company and its Restricted Subsidiaries
      under the New Credit Facility and the Foreign Credit Facilities; provided
      that the aggregate principal amount of all Indebtedness (with letters of
      credit being deemed to have a principal amount equal to the maximum
      potential liability of the Company and such Restricted Subsidiaries
      thereunder) then classified as having been incurred in reliance upon this
      clause (i) that remains outstanding (x) under the New Credit Facility
      after giving effect to such incurrence does not exceed an amount equal to
      $565.0 million or (y) under the Foreign Credit Facilities after giving
      effect to such incurrence does not exceed an amount equal to $10.0
      million;

            (ii) Existing Indebtedness;

            (iii) Indebtedness represented by the Notes and this Indenture;

            (iv) Indebtedness represented by Capital Expenditure Indebtedness,
      Capital Lease Obligations or other obligations, in each case, the proceeds
      of which are used solely for the purpose of financing all or any part of
      the purchase price or cost of construction or improvement of property,
      plant or equipment

                                       50
<PAGE>

      (including acquisitions of Capital Stock of a Person that becomes a
      Restricted Subsidiary to the extent of the fair market value of the
      property, plant or equipment so acquired) used in the business of the
      Company or such Restricted Subsidiary, in an aggregate principal amount
      (or accreted value, as applicable), including all Permitted Refinancing
      Indebtedness incurred to refund, refinance or replace any Indebtedness
      incurred pursuant to this clause (iv), not to exceed $30.0 million
      outstanding after giving effect to such incurrence;

            (v) Indebtedness arising from agreements of the Company or any
      Restricted Subsidiary providing for indemnification, adjustment of
      purchase price or similar obligations, in each case, incurred or assumed
      in connection with the disposition of any business, assets or a
      Subsidiary, other than guarantees of Indebtedness incurred by any Person
      acquiring all or any portion of such business, assets or Restricted
      Subsidiary for the purpose of financing such acquisition; provided that
      (A) such Indebtedness is not reflected on the balance sheet of the Company
      or any Restricted Subsidiary (contingent obligations referred to in a
      footnote or footnotes to financial statements and not otherwise reflected
      on the balance sheet will not be deemed to be reflected on such balance
      sheet for purposes of this clause (A)) and (B) the maximum assumable
      liability in respect of such Indebtedness shall at no time exceed the
      gross proceeds including non-cash proceeds (the fair market value of such
      non-cash proceeds being measured at the time received and without giving
      effect to any subsequent changes in value) actually received by the
      Company and/or such Restricted Subsidiary in connection with such
      disposition;

            (vi) the incurrence by the Company or any of its Restricted
      Subsidiaries of Permitted Refinancing Indebtedness;

            (vii) the incurrence by the Company or any of its Restricted
      Subsidiaries of intercompany Indebtedness between or among the Company
      and/or any of its Restricted Subsidiaries; provided that (A) any
      subsequent issuance or transfer of Equity Interests that results in any
      such Indebtedness being held by a Person other than the Company or a
      Restricted Subsidiary thereof and (B) any sale or other transfer of any
      such Indebtedness to a Person that is not either the Company or a
      Restricted Subsidiary thereof shall be deemed, in each case, to constitute
      an incurrence of such Indebtedness by the Company or such Restricted
      Subsidiary, as the case may be, that was not permitted by this clause
      (vii);

            (viii) the incurrence by the Company or any of its Restricted
      Subsidiaries of Hedging Obligations that are incurred for the purpose of
      fixing or hedging (A) interest rate risk with respect to any Indebtedness
      that is permitted by the terms of this Indenture to be outstanding and (B)
      exchange rate risk with respect to agreements or Indebtedness of such
      Person payable denominated in a currency other than U.S. dollars, provided
      that such agreements do not increase the Indebtedness of the obligor
      outstanding at any time other than as a result of fluctuations in foreign
      currency exchange rates or interest rates or by reason of fees,
      indemnities and compensation payable thereunder;

                                       51
<PAGE>

            (ix) 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
      Section 4.09;

            (x) the incurrence by the Company or any of its Restricted
      Subsidiaries of Indebtedness in connection with an acquisition in an
      aggregate principal amount (or accreted value, as applicable), including
      all Permitted Refinancing Indebtedness incurred to refund, refinance or
      replace any Indebtedness incurred pursuant to this clause (x), not to
      exceed $50.0 million outstanding after giving effect to such incurrence;

            (xi) obligations in respect of performance and surety bonds and
      completion guarantees (including related letters of credit) provided by
      the Company or any Restricted Subsidiary in the ordinary course of
      business; and

            (xii) the incurrence by the Company or any of its Restricted
      Subsidiaries of additional Indebtedness in an aggregate principal amount
      (or accreted value, as applicable) outstanding after giving effect to such
      incurrence, including all Permitted Refinancing Indebtedness incurred to
      refund, refinance or replace any Indebtedness incurred pursuant to this
      clause (xii), not to exceed $45.0 million.

      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 Indebtedness described in clauses (i) through (xii)
above or is entitled to be incurred pursuant to the first paragraph of this
Section 4.09, the Company shall, in its sole discretion, classify such item of
Indebtedness in any manner that complies with this Section 4.09 and such item of
Indebtedness will be treated as having been incurred pursuant to only one of
such clauses or pursuant to the first paragraph hereof of this Section 4.09. In
addition, the Company may, at any time, change the classification of an item of
Indebtedness (or any portion thereof) to any other clause or to the first
paragraph hereof; provided that the Company would be permitted to incur such
item of Indebtedness (or such portion thereof) pursuant to such other clause or
the first paragraph hereof of this Section 4.09, as the case may be, at such
time of reclassification. Accrual of interest, accretion or amortization of
original issue discount will 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 (a) the
Company or such Restricted Subsidiary, as the case may be, receives
consideration at the time of such Asset Sale at least equal to 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 assets or Equity
Interests issued or sold or otherwise disposed of and (b) at least 75% of the
consideration therefor received by the Company or such Restricted Subsidiary is
in the form of (i) cash or Cash Equivalents or (ii) property or assets that are
used or useful in a Permitted Business, or the Capital Stock of any Person
engaged in a Permitted Business if, as a result of the acquisition by the
Company or any Restricted Subsidiary thereof, such Person becomes a Restricted
Subsidiary; provided that the amount of (x) any liabilities (as shown on the
Company's or such Restricted Subsidiary's most recent

                                       52
<PAGE>

balance sheet), of the Company or any Restricted Subsidiary (other than
contingent liabilities and liabilities that are by their terms subordinated to
the Notes or any guarantee thereof) that are assumed by the transferee of any
such assets pursuant to a customary novation agreement that releases the Company
or such Restricted Subsidiary from further liability, (y) any securities, notes
or other obligations received by the Company or any such Restricted Subsidiary
from such transferee that are converted by the Company or such Restricted
Subsidiary into cash or Cash Equivalents within 180 days of their receipt by the
Company or such Restricted Subsidiary (but only to the extent of the cash or
Cash Equivalents received), and (z) any Designated Noncash Consideration
received by the Company or any of its Restricted Subsidiaries in such Asset Sale
having an aggregate fair market value, taken together with all other Designated
Noncash Consideration received pursuant to this clause (z) that is at that time
outstanding, not to exceed 15% of Total Assets at the time of the receipt of
such Designated Noncash Consideration (with the fair market value of each item
of Designated Noncash Consideration being measured at the time received and
without giving effect to subsequent changes in value), shall be deemed to be
cash for purposes of this Section 4.10; and provided further that the 75%
limitation referred to in clause (b) above will not apply to any Asset Sale in
which the cash or Cash Equivalents portion of the consideration received
therefrom, determined in accordance with the foregoing proviso, is equal to or
greater than what the after-tax proceeds would have been had such Asset Sale
complied with the aforementioned 75% limitation.

      Within 365 days after the receipt of any Net Proceeds from an Asset Sale,
the Company or any such Restricted Subsidiary, as the case may be, shall apply
such Net Proceeds, at its option (or to the extent the Company is required to
apply such Net Proceeds pursuant to the terms of the New Credit Facility), to
(a) repay or purchase Pari Passu Indebtedness of the Company or any Indebtedness
of any Restricted Subsidiary, as the case may be, provided that, if the Company
shall so repay or purchase Pari Passu Indebtedness of the Company, it will
equally and ratably reduce Indebtedness under the Notes if the Notes are then
redeemable, or, if the Notes may not then be redeemed, the Company shall make an
offer (in accordance with the procedures set forth below for an Asset Sale
Offer) to all Holders of Notes to purchase at a purchase price equal to 100% of
the Accreted Value of the Notes, plus accrued and unpaid interest, if any,
thereon to the date of purchase, the Notes that would otherwise be redeemed, or
(b) (i) an investment in property, the making of a capital expenditure or the
acquisition of assets that are used or useful in a Permitted Business, or (ii)
the acquisition of Capital Stock of any Person primarily engaged in a Permitted
Business if (x) as a result of the acquisition by the Company or any Restricted
Subsidiary thereof, such Person becomes a Restricted Subsidiary or (y) the
Investment in such Capital Stock is permitted by clause (f) of the definition of
Permitted Investments. Pending the final application of any such Net Proceeds,
the Company may temporarily reduce Indebtedness or otherwise invest such 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
first sentence of this paragraph will be deemed to constitute "Excess Proceeds."
When the aggregate amount of Excess Proceeds is greater than $10.0 million, the
Company will be required to make an offer to all Holders of Notes (an "Asset
Sale Offer") to purchase the maximum principal amount at maturity 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 Accreted Value thereof, plus accrued and unpaid
interest, if any, thereon to the date of purchase, in accordance with

                                       53
<PAGE>

the procedures set forth in this Indenture. To the extent that any Excess
Proceeds remain after consummation of an Asset Sale Offer, the Company may use
such Excess Proceeds for any purpose not otherwise prohibited by this Indenture.
If the aggregate Accreted Value of Notes surrendered by Holders thereof in
connection with an Asset Sale Offer exceeds the amount of Excess Proceeds, the
Trustee shall select the Notes to be purchased as set forth under Sections 3.02
and 3.03 hereof. Upon completion of such offer to purchase, the amount of Excess
Proceeds shall be reset at zero.

      The Company shall comply with the requirements of Rule 14e-1 under the
Exchange Act and any other securities laws and regulations thereunder to the
extent such laws and regulations are applicable in connection with the
repurchase of the Notes pursuant to an Asset Sale Offer. To the extent that the
provisions of any securities laws or regulations conflict with the provisions of
this Indenture relating to such Asset Sale Offer, the Company shall comply with
the applicable securities laws and regulations and shall not be deemed to have
breached its obligations described in this Indenture by virtue thereof.

      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, agreement, understanding, loan, advance or guarantee
with, or for the benefit of, any Affiliate of the Company (each of the
foregoing, an "Affiliate Transaction"), unless (a) such Affiliate Transaction is
on terms that are no less favorable to the Company or such 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 (b) the
Company delivers to the Trustee, with respect to any Affiliate Transaction or
series of related Affiliate Transactions involving aggregate consideration in
excess of $7.5 million, either (i) a resolution of the Board of Directors set
forth in an Officers' Certificate certifying that such Affiliate Transaction
complies with clause (a) above and that such Affiliate Transaction has been
approved by a majority of the disinterested members of the Board of Directors or
(ii) an opinion as to the fairness to the Holders of such 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 to
be Affiliate Transactions: (a) customary directors' fees, indemnification or
similar arrangements or any employment agreement or other compensation plan or
arrangement entered into by the Company or any of its Restricted Subsidiaries in
the ordinary course of business (including ordinary course loans to employees
not to exceed (i) $5.0 million outstanding in the aggregate at any time and (ii)
$2.0 million to any one employee) and consistent with the past practice of the
Company or such Restricted Subsidiary; (b) transactions between or among the
Company and/or its Restricted Subsidiaries; (c) payments of customary fees by
the Company or any of its Restricted Subsidiaries to DLJMB and its Affiliates
made for any financial advisory, financing, underwriting or placement services
or in respect of other investment banking activities, including, without
limitation, in connection with acquisitions or divestitures which are approved
by a majority of the Board of Directors in good faith; (d) any agreement as in
effect on the Date of Issuance or any amendment thereto (so long as such
amendment is not

                                       54
<PAGE>

disadvantageous to the Holders of the Notes in any material respect) or any
transaction contemplated thereby; (e) payments and transactions in connection
with the Acquisition and the Acquisition Financing including any purchase price
adjustment or any other payments made pursuant to the Acquisition Agreement or
the financial advisory agreements with Credit Suisse First Boston Corporation
and the New Credit Facility (including commitment, syndication and arrangement
fees payable thereunder) and the offering of the Notes and the application of
the proceeds thereof, and the payment of the fees and expenses with respect
thereto; (f) Restricted Payments that are permitted by Section 4.07 hereof and
any Permitted Investments; (g) sales of accounts receivable, or participations
therein, in connection with any Receivables Facility and (h) transactions with
Advanstar IH, Inc. and its Subsidiaries in the ordinary course of business.

      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, other than a Permitted Lien, that secures obligations
under any Pari Passu Indebtedness or subordinated Indebtedness of the Company on
any asset or property now owned or hereafter acquired by the Company or any of
its Restricted Subsidiaries, or any income or profits therefrom or assign or
convey any right to receive income therefrom, unless the Notes are equally and
ratably secured with the obligations so secured until such time as such
obligations are no longer secured by a Lien; provided that, in any case
involving a Lien securing subordinated Indebtedness of the Company, such Lien is
subordinated to the Lien securing the Notes to the same extent that such
subordinated Indebtedness is subordinated to the Notes.

      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 (i) the corporate, partnership or other existence of
itself and 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 (ii) 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 itself and 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. (a) Upon the
occurrence of a Change of Control, each Holder of Notes will have the right to
require the Company to repurchase all or any part (equal to $1,000 or an
integral multiple thereof) of such Holder's Notes pursuant to the offer
described below (the "Change of Control Offer") at an offer price in cash equal
to 101% of the aggregate Accreted Value thereof, plus accrued and unpaid
interest, if any, thereon to the date of repurchase (the "Change of Control
Payment"). Within 60 days following any Change of Control, the Company will (or
will cause the Trustee to) mail a notice to each Holder describing the
transaction or transactions that constitute the Change of Control and offering
to repurchase Notes on the date specified in such notice, which date 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"), pursuant to the procedures
required by this Indenture and

                                       55
<PAGE>

described in such notice. The Company shall comply with the requirements of Rule
14e-1 under the Exchange Act and any other securities laws and regulations
thereunder to the extent such laws and regulations are applicable in connection
with the repurchase of the Notes as a result of a Change of Control. To the
extent that the provisions of any securities laws or regulations conflict with
the provisions of this Indenture relating to such Change of Control Offer, the
Company shall comply with the applicable securities laws and regulations and
shall not be deemed to have breached its obligations described in this Indenture
by virtue thereof.

      On the Change of Control Payment Date, the Company shall, to the extent
lawful, (a) accept for payment all Notes or portions thereof properly tendered
pursuant to the Change of Control Offer, (b) deposit with the Paying Agent an
amount equal to the Change of Control Payment in respect of all Notes or
portions thereof so tendered and (c) deliver or cause to be delivered to the
Trustee the Notes so accepted together with an Officers' Certificate stating the
aggregate principal amount at maturity of Notes or portions thereof being
purchased by the Company. The Paying Agent will promptly mail to each Holder of
Notes so tendered the Change of Control Payment for such Notes, and the Trustee
will promptly authenticate and mail (or cause to be transferred by book- entry)
to each Holder a new Note equal in principal amount at maturity to any
unpurchased portion of the Notes surrendered, if any; provided that each such
new Note will be in a principal amount at maturity of $1,000 or an integral
multiple thereof. Prior to complying with the provisions of this Section 4.14,
but in any event within 90 days following a Change of Control, the Company shall
either repay all outstanding Indebtedness or obtain the requisite consents, if
any, under all agreements governing outstanding Indebtedness to permit the
repurchase of Notes required by this Section 4.14. 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.

      (b) Notwithstanding anything to the contrary in this Section 4.14, the
Company will 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 validly tendered and not withdrawn under such Change of
Control Offer.

      SECTION 4.15. Limitation on 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 that the Company or any
Restricted Subsidiary may enter into a sale and leaseback transaction if (a) the
Company or such Restricted Subsidiary, as the case may be, could have (i)
incurred Indebtedness in an amount equal to the Attributable Indebtedness
relating to such sale and leaseback transaction pursuant to the Leverage Ratio
test set forth in the first paragraph of Section 4.09 hereof and (ii) incurred a
Lien to secure such Indebtedness pursuant to Section 4.12 hereof, (b) 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 and set
forth in an Officers' Certificate delivered to the Trustee) of the property that
is the subject of such sale and leaseback transaction and (c) the transfer of
assets in such sale and leaseback transaction is permitted by, and the Company
applies the proceeds of such transaction in compliance with, Section 4.10
hereof.

                                       56
<PAGE>

                                    ARTICLE 5
                                   SUCCESSORS

      SECTION 5.01. Merger, Consolidation, or Sale of Assets. The Company may
not consolidate or merge with or into (whether or not the Company is the
surviving corporation), or sell, assign, transfer, convey or otherwise dispose
of all or substantially all of its properties or assets in one or more related
transactions, to another Person unless (a) the Company is the surviving
corporation or the Person formed by or surviving any such consolidation or
merger (if other than the Company) or to which such sale, assignment, transfer,
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 Person formed by or surviving any such
consolidation or merger (if other than the Company) or the Person to which such
sale, assignment, transfer, conveyance or other disposition shall have been made
assumes all the obligations of the Company under the Registration Rights
Agreement, 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 or Event of Default exists and (d) the Company or the
Person formed by or surviving any such consolidation or merger (if other than
the Company), or to which such sale, assignment, transfer, conveyance or other
disposition shall have been made (i) will, at the time of such transaction and
after giving pro forma effect thereto as if such transaction had occurred at the
beginning of the applicable four-quarter period, be permitted to incur at least
$1.00 of additional Indebtedness pursuant to the Leverage Ratio test set forth
in the first paragraph of Section 4.09 hereof or (ii) would (together with its
Restricted Subsidiaries) have a lower Leverage Ratio immediately after such
transaction (after giving pro forma effect thereto as if such transaction had
occurred at the beginning of the applicable four-quarter period) than the
Leverage Ratio of the Company and its Restricted Subsidiaries immediately prior
to such transaction. The foregoing clause (d) will not prohibit (a) a merger
between the Company and a Wholly Owned Subsidiary of Holdings created for the
purpose of holding the Capital Stock of the Company, (b) a merger between the
Company and a Wholly Owned Restricted Subsidiary or (c) a merger between the
Company and an Affiliate incorporated solely for the purpose of reincorporating
the Company in another State of the United States so long as, in each case, the
amount of Indebtedness of the Company and its Restricted Subsidiaries is not
increased thereby. The Company shall not lease all or substantially all of its
assets to any Person.

      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

                                       57
<PAGE>

the Notes except in the case of a sale of all or substantially 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:

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

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

            (c) failure by the Company or any of its Restricted Subsidiaries for
      30 days after receipt of notice from the Trustee or Holders of at least
      25% in principal amount at maturity of the Notes then outstanding to
      comply with Sections 4.07, 4.09, 4.10, 4.14 or Article 5 hereof;

      (d) failure by the Company for 60 days after notice from the Trustee or
the Holders of at least 25% in principal amount at maturity of the Notes then
outstanding to comply with any of its other agreements in this Indenture or the
Notes;

            (e) 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 Restricted
      Subsidiaries (or the payment of which is guaranteed by the Company or any
      of its Restricted Subsidiaries), whether such Indebtedness or guarantee
      now exists, or is created after the Date of Issuance, which default (i) is
      caused by a failure to pay Indebtedness at its stated final maturity
      (after giving effect to any applicable grace period provided in such
      Indebtedness) (a "Payment Default") or (ii) results in the acceleration of
      such Indebtedness prior to its stated final maturity and, in each case,
      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;

            (f) failure by the Company or any of its Restricted Subsidiaries to
      pay final judgments aggregating in excess of $20.0 million (net of any
      amounts with respect to which a reputable and creditworthy insurance
      company has acknowledged liability in writing), which judgments are not
      paid, discharged or stayed for a period of 60 days;

            (g) the Company or any of its Restricted Subsidiaries that is a
      Significant Subsidiary or any group of Restricted Subsidiaries that, taken
      as a

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<PAGE>

      whole, would constitute a Significant Subsidiary pursuant to or within the
      meaning of Bankruptcy Law:

                  (i) commences a voluntary case,

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

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

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

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

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

                  (i) is for relief against the Company or any of its Restricted
            Subsidiaries that is a Significant Subsidiary or any group of
            Restricted Subsidiaries that, taken as a whole, would constitute a
            Significant Subsidiary in an involuntary case;

                  (ii) appoints a Custodian of the Company or any of its
            Restricted Subsidiaries that is a Significant Subsidiary or any
            group of Restricted Subsidiaries that, taken as a whole, would
            constitute a Significant Subsidiary or for all or substantially all
            of the property of the Company or any of its Restricted Subsidiaries
            that is a Significant Subsidiary or any group of Restricted
            Subsidiaries that, taken as a whole, would constitute a Significant
            Subsidiary; or

                  (iii) orders the liquidation of the Company or any of its
            Restricted Subsidiaries that is a Significant Subsidiary or any
            group of Restricted Subsidiaries that, taken as a whole, would
            constitute a Significant Subsidiary;

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

      SECTION 6.02. Acceleration. If any Event of Default (other than an Event
of Default specified in clause (g) or (h) of Section 6.01 hereof with respect to
the Company, any Restricted Subsidiaries that is a Significant Subsidiary or any
group of Restricted Subsidiaries that, taken as a whole, would constitute a
Significant Subsidiary) occurs and is continuing, the Holders of at least 25% in
principal amount at maturity of the then outstanding Notes may direct the
Trustee to declare the Accreted Value of the Notes, together with all accrued
and unpaid interest, to be due and payable immediately. Upon any such
acceleration, the Accreted Value of the Notes, together will all accrued and
unpaid interest, shall become due and payable immediately. Notwithstanding the
foregoing, if an Event of Default specified in clause (g) or (h) of Section 6.01
hereof

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<PAGE>

occurs with respect to the Company, any of its Restricted Subsidiaries that is a
Significant Subsidiary or any group of Restricted Subsidiaries that, taken as a
whole, would constitute a Significant Subsidiary, the Accreted Value and all
accrued and unpaid interest on all outstanding Notes shall become due and
payable immediately without further action or notice. Holders of the Notes may
not enforce this Indenture or the Notes except as provided in this Indenture.
The Holders of a majority in aggregate principal amount at maturity 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, if any, that has become
due solely because of the acceleration) have been cured or waived; provided
that, in the event of a declaration of acceleration of the Notes because an
Event of Default has occurred and is continuing as a result of the acceleration
of any Indebtedness described in clause (e) of Section 6.01 hereof, the
declaration of acceleration of the Notes shall be automatically annulled if the
holders of any Indebtedness described in clause (e) of Section 6.01 hereof have
rescinded the declaration of acceleration in respect of such Indebtedness within
30 days of the date of such declaration and if (i) the annulment of the
acceleration of the Notes would not conflict with any judgment or decree of a
court of competent jurisdiction and (ii) all existing Events of Default, except
non-payment of principal or interest on the Notes that became due solely because
of the acceleration of the Notes, 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, 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 at maturity 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 at maturity 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.

      SECTION 6.05. Control by Majority. Holders of a majority in principal
amount at maturity of the then outstanding Notes may direct the time, method and
place of

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<PAGE>

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:

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

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

            (c) 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;

            (d) 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

            (e) during such 60-day period the Holders of a majority in principal
      amount at maturity 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, 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.

      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 Accreted Value of, premium, if any, and interest
remaining unpaid on the Notes and interest, if any, 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

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<PAGE>

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 6, 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, 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, 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,

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<PAGE>

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 at maturity 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 man would exercise or use under the circumstances in the
conduct of his 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 to
      determine whether or not they conform to the requirements of this
      Indenture.

      (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 7.01;

            (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), (c), (e) and (f) of this Section 7.01 and Section 7.02 hereof.

      (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

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<PAGE>

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 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 and the written 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.

      (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.

      (g) Except with respect to Section 4.01 hereof, the Trustee shall have no
duty to inquire as to the performance of the Company's covenants in Article 4
hereof. In addition, the Trustee shall not be deemed to have knowledge of any
Default or Event of Default except (i) any Event of Default occurring pursuant
to Sections 6.01(a), 6.01(b) and 4.01 or (ii) any Default or Event of Default of
which the Trustee shall have received written notification or obtained actual
knowledge.

      (h) The Trustee shall not be bound to make any investigation into the
facts or matters stated in any resolution, certificate, statement, instrument,
opinion, report, notice, request, direction, consent, order, bond, debenture,
note, other evidence of indebtedness or other paper or document, but the Trustee
may, in its discretion, make such further inquiry or investigation into such
facts or matters as it may see fit and if the Trustee shall

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<PAGE>

determine to make such further inquiry or investigation, it shall be entitled to
examine the books, records and premises of the Company personally or by agent or
attorney.

      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 Commission 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 known to 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. (b)(2). The Trustee
shall also transmit by mail all reports as required by TIA ss. 313(c).

      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 Commission 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.

      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

                                       65
<PAGE>

include the reasonable compensation, disbursements and expenses of the Trustee's
agents and counsel.

      The Company shall indemnify the Trustee against any and all losses,
liabilities or 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 may be attributable to its
negligence or bad faith. 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.

      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.

      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 Notes of a
majority in principal amount at maturity 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;

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<PAGE>

            (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 at maturity 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 Notes of at least 10% in principal amount at maturity of the then
outstanding Notes may petition any court of competent jurisdiction for the
appointment of a successor Trustee.

      If the Trustee, after written request by any Holder of a Note who has been
a Holder of a Note for at least six months, fails to comply with Section 7.10
hereof, such Holder of a Note 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 of the Notes. 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. Notwithstanding replacement of the Trustee pursuant to this Section
7.08, the Company's obligations under Section 7.07 hereof shall continue for the
benefit of the retiring Trustee.

      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 $100 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).

      SECTION 7.11. Preferential Collection of Claims Against Company. The
Trustee is subject to TIAss. 311(a), excluding any creditor relationship listed
in TIA ss. 311(b). A

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<PAGE>

Trustee who has resigned or been removed shall be subject to TIA ss. 311(a) to
the extent indicated therein.

                                    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 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 and this Indenture 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 and
this Indenture, 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 (a) and (b) 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
acknowledging the same), except for the following provisions which shall survive
until otherwise terminated or discharged hereunder:

            (a) the rights of Holders of outstanding Notes to receive payments
      in respect of the principal of, premium, if any, and interest on such
      Notes when such payments are due from the trust referred to below,

            (b) the Company's obligations with respect to the Notes concerning
      issuing temporary Notes, registration of Notes, mutilated, destroyed, lost
      or stolen Notes and the maintenance of an office or agency for payment and
      money for security payments held in trust,

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

            (d) the Legal Defeasance provisions of this Indenture.

      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 and 4.15 hereof with respect
to the outstanding Notes on and after the date the conditions set forth in
Section 8.04 are satisfied (hereinafter, "Covenant

                                       68
<PAGE>

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, 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(c) through 6.01(f) 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,

            (a) the Company must irrevocably deposit with the Trustee, in trust,
      for the benefit of the Holders of the Notes, cash in U.S. 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 maturity or on
      the applicable redemption date, as the case may be, and the Company must
      specify whether the Notes are being defeased to maturity or to a
      particular redemption date;

            (b) in the case of Legal Defeasance, the Company shall have
      delivered to the Trustee an Opinion of Counsel in the United States
      reasonably acceptable to the Trustee confirming that (i) the Company has
      received from, or there has been published by, the Internal Revenue
      Service a ruling or (ii) since the Date of Issuance, 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,
      subject to customary assumptions and exclusions, 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;

            (c) in the case of Covenant Defeasance, the Company shall have
      delivered to the Trustee an Opinion of Counsel in the United States
      reasonably acceptable to the Trustee confirming that, subject to customary
      assumptions and exclusions, 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

                                       69
<PAGE>

      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;

            (d) no Default or Event of Default shall have occurred and be
      continuing 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, insofar as Events of Default from bankruptcy or insolvency
      events are concerned, at any time in the period ending on the 123rd day
      after the date of deposit;

            (e) such Legal Defeasance or Covenant Defeasance will 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 Subsidiaries is a party or by which the Company or any of
      its Subsidiaries is bound;

            (f) the Company must have delivered to the Trustee an Opinion of
      Counsel to the effect that, subject to customary assumptions and
      exclusions, after the 123rd day following the deposit, the trust funds
      will not be subject to the effect of Section 547 of the United States
      Bankruptcy Code or any analogous New York State law provision or any other
      applicable federal or New York bankruptcy, insolvency, reorganization or
      similar laws affecting creditors' rights generally;

            (g) the Company must deliver to the Trustee an Officers' Certificate
      stating that the deposit was not made by the Company with the intent of
      preferring the Holders of Notes over the other creditors of the Company
      with the intent of defeating, hindering, delaying or defrauding creditors
      of the Company or others; and

            (h) the Company must deliver to the Trustee an Officers' Certificate
      and an Opinion of Counsel (which opinion may be subject to customary
      assumptions and exclusions), each stating that all conditions precedent
      provided for 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 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.

                                       70
<PAGE>

      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, as a secured creditor, 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 trustees
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
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.

                                       71
<PAGE>

                                    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 a Note:

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

            (b) 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;

            (c) 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;

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

            (e) to comply with requirements of the Commission in order to effect
      or maintain the qualification of this Indenture under the TIA.

      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 the
consent of the Holders of at least a majority in principal amount at maturity of
the Notes then outstanding voting as a single class (including 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 a 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 at maturity 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). Notwithstanding the foregoing, any amendment to or waiver of Sections
4.10 and 4.14 hereof will require the consent of the Holders of at least
two-thirds in aggregate principal amount at

                                       72
<PAGE>

maturity of the Notes then outstanding if such amendment would materially
adversely affect the rights of Holders of Notes.

      Notwithstanding the foregoing paragraph and except as otherwise provided
below in this Section 9.02, if DLJ Investment Partners II, L.P. owns at least
25% of the principal amount at maturity of the Notes then outstanding voting as
a single class, any amendment or supplement to this Indenture or the Notes, and
subject to Sections 6.04 and 6.07 hereof, any waiver of any existing Default or
Event of Default (except as stated above) or of compliance with any provision of
this Indenture or the Note shall require the consent of the Holders of at least
75% of the principal amount at maturity of the Notes then outstanding voting as
a single class.

      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 9.02 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 at maturity 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):

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

            (b) reduce the principal of or change the fixed maturity of any Note
      or alter the provisions with respect to the redemption of the Notes (other
      than Sections 4.10 and 4.14 hereof),

            (c) reduce the rate of or extend the time for payment of interest on
      any Note,

                                       73
<PAGE>

            (d) waive a 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 at maturity of the Notes and a waiver of the
      payment default that resulted from such acceleration),

            (e) make any Note payable in money other than that stated in the
      Notes,

            (f) make any change in the provisions of this Indenture relating to
      waivers of past Defaults,

            (g) waive a redemption payment with respect to any Note (other than
      Sections 4.10 and 4.14 hereof), or

            (h) make any change 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 an 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.

      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 its 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

                                       74
<PAGE>

required by Section 10.04 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
                                  MISCELLANEOUS

      SECTION 10.01. 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 10.02. 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 receipt requested),
telex, telecopier or overnight air courier guaranteeing next day delivery, to
the others' address.

      If to the Company:

               Advanstar, Inc.
               545 Boylston Street
               9th Floor
               Boston, Massachusetts 02110
               Telecopier No.: (617) 267-6900
               Attention:  General Counsel

      With a copy to:

               Davis Polk & Wardwell
               450 Lexington Avenue
               New York, New York  10017
               Telecopier No.:  (212) 450-4800
               Attention:  Richard Truesdell, Esq.

      If to the Trustee:

               Wells Fargo Bank Minnesota, N.A.
               Sixth & Marquette
               N9303-110
               Minneapolis, MN 55479
               Telecopier No.: 612-667-2160
               Attention: Corporate Trust Services -- Advanstar, Inc.

      The Company or the Trustee, by notice to the other 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

                                       75
<PAGE>

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 ss. 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 10.03. Communication by Holders of Notes with Other Holders of
Notes. Holders may communicate pursuant to TIA ss. 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 ss.
312(c).

      SECTION 10.04. 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 10.05 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 10.05 hereof) stating that, in the opinion of such counsel, all
      such conditions precedent and covenants have been satisfied.

      SECTION 10.05. 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;

                                       76
<PAGE>

            (c) a statement that, in the opinion of such Person, he or she has
      made such examination or investigation as is necessary to enable him 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 10.06. 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.

      SECTION 10.07. No Personal Liability of Directors, Officers, Employees and
Stockholders. No member, director, officer, employee, incorporator or
stockholder of the Company, as such, shall have any liability for any
obligations of the Company under the Notes or this Indenture or for any claim
based on, in respect of, or by reason of, such obligations or their creation.
Each Holder of 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.

      SECTION 10.08. 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 10.09. 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 10.10. 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 10.11. 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 10.12. 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 10.13. 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]

                                       77
<PAGE>

                                   SIGNATURES

Dated as of February 21, 2001

                                            ADVANSTAR, INC.

                                            By: ________________________________
                                                Name:
                                                Title:

                                            WELLS FARGO BANK MINNESOTA, N.A.,
                                                  as trustee

                                            By: ________________________________
                                                Name:
                                                Title:

                                       78
<PAGE>

                                                                     EXHIBIT A-1

                              (Face of Global Note)

                                                             CUSIP/CINS ________

                    15.0% Senior Discount Debentures due 2011

No. __                                                                $_________

                                 ADVANSTAR, INC.

promises to pay to _______________, or registered assigns, the principal sum of
____________ Dollars on October 15, 2011.

Interest Payment Dates:               April 15 and October 15, beginning with
                                      April 15, 2006

Record Dates:
                                      April 1 and October 1, beginning with
                                      April 1, 2006

                                      Dated:

                                      Advanstar, Inc.

                                      By:_______________________________________
                                             Name:
                                             Title:

This is one of the Global Notes
referred to in the within-mentioned
Indenture:

_____________________,
as Trustee

By: ______________________________
    Name:

                                      A-1-1
<PAGE>

                                 (Back of Note)

                    15.0% Senior Discount Debentures due 2011

[Insert the following if the Note is issued in global form.]

[Unless and until it is exchanged in whole or in part for Notes in definitive
form, this Note may not be transferred except as a whole by the Depositary to a
nominee of the Depositary or by a nominee of the Depositary to the Depositary or
another nominee of the Depositary or by the Depositary or any such nominee to a
successor Depositary or a nominee of such successor Depositary. Unless this
certificate is presented by an authorized representative of The Depository Trust
Company (55 Water Street, New York, New York) ("DTC"), to the issuer or its
agent for registration of transfer, exchange or payment, and any certificate
issued is registered in the name of Cede & Co. or such other name as may be
requested by an authorized representative of DTC (and any payment is made to
Cede & Co. or such other entity as may be requested by an authorized
representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL in as much as the registered owner
hereof, Cede & Co., has an interest herein.]

[Insert the Private Placement legend, if applicable, pursuant to the provisions
of the Indenture]

[If the Note is issued as part of a Unit prior to the Separation Date, then
insert - THE NOTES EVIDENCED BY THIS CERTIFICATE ARE INITIALLY ISSUED AS PART OF
AN ISSUANCE OF UNITS (THE "UNITS"), EACH OF WHICH CONSISTS OF $1,000 PRINCIPAL
AMOUNT AT MATURITY OF THE 15% SENIOR DISCOUNT DEBENTURES DUE 2011 OF ADVANSTAR,
INC. (THE "NOTES") AND ONE WARRANT (THE "WARRANTS") INITIALLY ENTITLING THE
HOLDER THEREOF TO PURCHASE 8.39122 SHARES, PAR VALUE $0.01 PER SHARE, OF COMMON
STOCK OF ADVANSTAR HOLDINGS CORP.

PRIOR TO THE EARLIEST TO OCCUR OF (I)180 DAYS AFTER THE CLOSING OF THE OFFERING
OF THE UNITS, (II) THE DATE ON WHICH A REGISTRATION STATEMENT WITH RESPECT TO A
REGISTERED EXCHANGE OFFER FOR THE NOTES IS DECLARED EFFECTIVE UNDER THE
SECURITIES ACT, (III) THE DATE ON WHICH A REGISTRATION STATEMENT WITH RESPECT TO
THE COMMON STOCK UNDERLYING THE WARRANTS IS DECLARED EFFECTIVE UNDER THE
SECURITIES ACT, (IV) SUCH DATE AS CREDIT SUISSE FIRST BOSTON CORPORATION IN ITS
SOLE DISCRETION SHALL DETERMINE AND (V) IN THE EVENT OF THE OCCURRENCE OF A
CHANGE OF CONTROL (AS DEFINED IN THE INDENTURE GOVERNING THE NOTES) THE DATE ON
WHICH THE REQUISITE NOTICE IS MAILED TO HOLDERS OF NOTES, THE NOTES EVIDENCED BY
THIS CERTIFICATE MAY NOT BE TRANSFERRED OR EXCHANGED SEPARATELY FROM, BUT MAY BE
TRANSFERRED OR EXCHANGED ONLY TOGETHER WITH, THE WARRANTS.]

                                      A-1-2
<PAGE>

Capitalized terms used herein shall have the meanings assigned to them in the
Indenture referred to below unless otherwise indicated.

      1. Interest. No interest will accrue on the Notes prior to October 15,
2005. Advanstar, Inc., a Delaware corporation (the "Company"), promises to pay
interest on the principal amount at maturity of this Note at 15.0% per annum
from October 15, 2005 until maturity. The Company will pay interest
semi-annually on April 15 and October 15 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 October 15, 2005;
provided that if there is no 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; and provided further that the first
Interest Payment Date shall be April 15, 2006. The Company shall pay interest
(including post-petition interest in any proceeding under any Bankruptcy Law) on
overdue principal and premium, 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 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 April 1 or October 1 next preceding the Interest
Payment Date, even if such Notes are cancelled 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 of the Paying Agent and
Registrar. Holders of Notes must surrender their Notes to the Paying Agent to
collect principal payments, and the Company may pay principal and interest by
check and may mail checks to a Holder's registered address; provided that all
payments with respect to Global Notes and Definitive Notes, the Holders of which
have given wire transfer instructions to the Company, will be required to be
made by wire transfer of immediately available funds to the accounts specified
by the Holders thereof. 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 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 of
February 21, 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 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

                                      A-1-3
<PAGE>

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 initially limited to $171,792,000 in aggregate principal amount at
maturity.

      5. Optional Redemption.

      (a) The Notes will be subject to redemption at any time at the option of
the Company, in whole or in part, upon not less than 30 nor more than 60 days'
notice, in cash at the redemption prices (expressed as percentages of Accreted
Value) equal to 115.000%, if redeemed at any time from the Date of Issuance
until October 15, 2005, and at the redemption prices set forth below, plus
accrued and unpaid interest, if any, thereon to the applicable redemption date,
if redeemed during the twelve-month period beginning on October 15 of the years
indicated below:

           Year                                      Percentage
           ----                                      ----------
           2005....................................  107.500%
           2006....................................  103.750%
           2007....................................  101.875%
           2008 and thereafter.....................  100.000%

      (b) Any redemption pursuant to this subparagraph 5 shall be made pursuant
to the provisions of Sections 3.01 through 3.06 of the Indenture.

      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.

      7. Repurchase at Option of Holder.

      (a) Upon the occurrence of a Change of Control, each Holder of Notes will
have the right to require the Company to repurchase all or any part (equal to
$1,000 principal amount at maturity or an integral multiple thereof) of such
Holder's Notes pursuant to the offer described in Section 4.14 of the Indenture
(the "Change of Control Offer") at an offer price in cash equal to 101% of the
aggregate Accreted Value thereof plus accrued and unpaid interest, if any, to
the date of purchase (the "Change of Control Payment"). Within 60 days following
any Change of Control, the Company will (or will cause the Trustee to) mail a
notice to each Holder describing the transaction or transactions that constitute
the Change of Control and offering to repurchase Notes on the date specified in
such notice, which date shall be no earlier than 30 days and no later than 60
days from the date such notice is mailed, pursuant to the procedures required by
the Indenture and described in such notice.

      (b) Any Net Proceeds from Asset Sales that are not applied or invested as
provided in Section 4.10 of the Indenture will be deemed to constitute "Excess
Proceeds." When the aggregate amount of Excess Proceeds is greater than $10.0
million, the Company will be required to make an offer to all Holders of Notes
(an "Asset Sale

                                      A-1-4
<PAGE>

Offer") to purchase the maximum principal amount at maturity 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 Accreted Value thereof, plus accrued and unpaid interest,
if any, thereon to the date of purchase, in accordance with the procedures set
forth in this Indenture. To the extent that any Excess Proceeds remain after
consummation of an Asset Sale Offer, the Company may use such Excess Proceeds
for any purpose not otherwise prohibited by this Indenture. If the aggregate
Accreted Value of Notes surrendered by Holders thereof in connection with an
Asset Sale Offer exceeds the amount of Excess Proceeds, the Trustee shall select
the Notes to be purchased as set forth under Sections 3.02 and 3.03 of the
Indenture. Upon completion of such offer to purchase, the amount of Excess
Proceeds shall be reset at zero. Holders of Notes that are the subject of an
offer to purchase may elect to have such Notes purchased by completing the form
entitled "Option of Holder to Elect Purchase" on the reverse of the Notes.

      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 principal amount at maturity may be redeemed in part but only
in whole multiples of $1,000 principal amount at maturity, 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 principal amount at maturity and
integral multiples of $1,000 principal amount at maturity. 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 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 at maturity 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 at maturity of the then outstanding Notes. Without
the consent of any Holder of a Note, 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

                                      A-1-5
<PAGE>

not materially adversely affect the legal rights under the Indenture of any such
Holder or to comply with the requirements of the Commission in order to effect
or maintain the qualification of the Indenture under the TIA.

      12. Defaults and Remedies. If any Event of Default specified in the
Indenture (other than certain events of bankruptcy or insolvency) occurs and is
continuing, the Holders of at least 25% in principal amount at maturity of the
then outstanding Notes may direct the Trustee to declare the Accreted Value and
all accrued and unpaid interest on all the Notes to be due and payable
immediately. Upon any such declaration, the Accreted Value and all accrued and
unpaid interest on the Notes shall become due and payable immediately.
Notwithstanding the foregoing, in the case of an Event of Default arising from
certain events of bankruptcy or insolvency, the Accreted Value and all accrued
and unpaid interest on all outstanding Notes shall be due and payable
immediately without further action or notice. Holders of the Notes may not
enforce the Indenture or the Notes except as provided in the Indenture. The
Holders of a majority in aggregate principal amount at maturity 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 or interest that has become due solely because
of the acceleration) have been cured or waived; provided that, in the event of a
declaration of acceleration of the Notes because an Event of Default has
occurred and is continuing as a result of the acceleration of any Indebtedness
described in clause (e) of Section 6.01 of the Indenture, the declaration of
acceleration of the Notes shall be automatically annulled if the holders of any
Indebtedness described in clause (e) of Section 6.01 of the Indenture have
rescinded the declaration of acceleration in respect of such Indebtedness within
30 days of the date of such declaration and if (i) the annulment of the
acceleration of the Notes would not conflict with any judgment or decree of a
court of competent jurisdiction and (ii) all existing Events of Default, except
non-payment of principal or interest on the Notes that became due solely because
of the acceleration of the Notes, have been cured or waived. 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.

                                      A-1-6
<PAGE>

      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. Additional Rights of Holders of Restricted Global Notes and Restricted
Definitive Notes. In addition to the rights provided to Holders of Notes under
the Indenture, Holders of Restricted Global Notes and Restricted Definitive
Notes shall have all the rights set forth in the Debt Registration Rights
Agreement dated as of February 21, 2001, between the Company and the parties
named on the signature pages thereof (the "Registration Rights Agreement").

      18. 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 and/or the Registration Rights Agreement.
Requests may be made to:

      Advanstar, Inc.
      545 Boylston Street
      9th Floor
      Boston, Massachusetts 02110
      Telecopier No.: (617) 267-6900
      Attention:  General Counsel

                                      A-1-7
<PAGE>

                                 Assignment Form

To assign this Note, fill in the form below: (I) or (we) assign and transfer
this Note to

(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 Note)

                                    Tax Identification No.: ____________________

Signature Guarantee.

                                      A-1-8
<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 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
principal amount at maturity you elect to have purchased: $________

Date:                               Your Signature:_____________________________
                                                   (Sign exactly as your name
                                                   appears on the Note)

                                    Tax Identification No.: ____________________

Signature Guarantee.

                                      A-1-9
<PAGE>

            SCHEDULE OF EXCHANGES OF INTERESTS IN THE GLOBAL NOTE(1)

      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
                                                                        At Maturity          Signature of
                  Amount of decrease in      Amount of increase       of this Global      authorized officer
                     Principal Amount       in Principal Amount       Note following              of
 Date of               At Maturity               At Maturity           such decrease        Trustee or Note
 Exchange          of this Global Note       of this Global Note       (or increase)          Custodian
 --------         ----------------------    --------------------     ----------------     ------------------
<S>               <C>                        <C>                      <C>                    <C>

</TABLE>

----------
(1)   This should be included only if the Note is issued in global form.

                                     A-1-10
<PAGE>

                                                                     EXHIBIT A-2

                  (Face of Regulation S Temporary Global Note)

================================================================================

                                                            CUSIP/CINS__________

                    15.0% Senior Discount Debentures due 2011

No.__                                                                 $_________

                                 ADVANSTAR, INC.

promises to pay to _______________, or registered assigns, the principal sum of
__________ Dollars on October 15, 2011.

Interest Payment Dates: April 15 and October 15, beginning with April 15, 2006

Record Dates: April 1 and October 1, beginning with April 1, 2006

                                                   Dated:

                                                   ADVANSTAR, INC.

                                                   By:__________________________

                                                       Name:
                                                       Title:

This is one of the Global Notes
referred to in the within-mentioned
Indenture:

___________________,
as Trustee

By:_______________________________
   Name:

================================================================================
<PAGE>

                  (Back of Regulation S Temporary Global Note)

                    15.0% Senior Discount Debentures due 2011

THE RIGHTS ATTACHING TO THIS REGULATION S TEMPORARY GLOBAL NOTE, AND THE
CONDITIONS AND PROCEDURES GOVERNING ITS EXCHANGE FOR CERTIFICATED NOTES, ARE AS
SPECIFIED IN THE INDENTURE (AS DEFINED HEREIN). NEITHER THE HOLDER NOR THE
BENEFICIAL OWNERS OF THIS REGULATION S TEMPORARY GLOBAL NOTE SHALL BE ENTITLED
TO RECEIVE PAYMENT OF INTEREST HEREON.

"THE SECURITY (OR ITS PREDECESSOR) EVIDENCED HEREBY WAS ORIGINALLY ISSUED IN A
TRANSACTION EXEMPT FROM REGISTRATION UNDER SECTION 5 OF THE UNITED STATES
SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND THE SECURITY
EVIDENCED HEREBY MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED IN THE
ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION THEREFROM. EACH
PURCHASER OF THE SECURITY EVIDENCED HEREBY IS HEREBY NOTIFIED THAT THE SELLER
MAY BE RELYING ON THE EXEMPTION FROM THE PROVISIONS OF SECTION 5 OF THE
SECURITIES ACT PROVIDED BY RULE 144A OR REGULATION S THEREUNDER. THE HOLDER OF
THE SECURITY EVIDENCED HEREBY AGREES FOR THE BENEFIT OF THE COMPANY THAT (A)
SUCH SECURITY MAY BE RESOLD, PLEDGED OR OTHERWISE TRANSFERRED, ONLY (1)(a)
INSIDE THE UNITED STATES TO A PERSON WHO THE SELLER REASONABLY BELIEVES IS A
QUALIFIED INSTITUTIONAL BUYER (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT)
IN A TRANSACTION MEETING THE REQUIREMENTS OF RULE 144A, (b) IN A TRANSACTION
MEETING THE REQUIREMENTS OF RULE 144 UNDER THE SECURITIES ACT, (c) OUTSIDE THE
UNITED STATES TO A FOREIGN PERSON IN A TRANSACTION MEETING THE REQUIREMENTS OF
RULE 904 UNDER THE SECURITIES ACT, (d) TO AN INSTITUTIONAL "ACCREDITED INVESTOR"
AS DEFINED IN RULE 501(A)(1), (2), (3) OR (7) OF THE SECURITIES ACT (AN
"INSTITUTIONAL ACCREDITED INVESTOR") THAT, PRIOR TO SUCH TRANSFER, FURNISHES THE
TRUSTEE A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS (THE
FORM OF WHICH CAN BE OBTAINED FROM THE TRUSTEE) AND, IF SUCH TRANSFER IS IN
RESPECT OF NOTES WITH AN AGGREGATE ACCRETED VALUE OF LESS THAN $250,000, AN
OPINION OF COUNSEL THAT SUCH TRANSFER IS IN COMPLIANCE WITH THE SECURITIES ACT
OR (e) IN ACCORDANCE WITH ANOTHER EXEMPTION FROM THE REGISTRATION REQUIREMENTS
OF THE SECURITIES ACT (AND BASED UPON AN OPINION OF COUNSEL IF THE COMPANY SO
REQUESTS), (2) TO THE COMPANY OR (3) PURSUANT TO AN EFFECTIVE REGISTRATION
STATEMENT AND, IN EACH CASE, IN ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS
OF ANY STATE OF THE UNITED STATES OR ANY OTHER APPLICABLE JURISDICTION AND (B)
THE HOLDER WILL, AND EACH SUBSEQUENT HOLDER IS REQUIRED TO, NOTIFY ANY PURCHASER
FROM IT OF THE SECURITY EVIDENCED HEREBY OF THE RESALE RESTRICTIONS SET FORTH IN
(A) ABOVE."

                                      A-2-2
<PAGE>

      Capitalized terms used herein shall have the meanings assigned to them in
the Indenture referred to below unless otherwise indicated.

      [If the Note is issued as part of a Unit prior to the Separation Date,
then insert - THE NOTES EVIDENCED BY THIS CERTIFICATE ARE INITIALLY ISSUED AS
PART OF AN ISSUANCE OF UNITS (THE "UNITS"), EACH OF WHICH CONSISTS OF $1,000
PRINCIPAL AMOUNT AT MATURITY OF THE 15% SENIOR DISCOUNT DEBENTURES DUE 2011 OF
ADVANSTAR, INC. (THE "NOTES") AND ONE WARRANT (THE "WARRANTS") INITIALLY
ENTITLING THE HOLDER THEREOF TO PURCHASE 8.39122 SHARES, PAR VALUE $0.01 PER
SHARE, OF COMMON STOCK OF ADVANSTAR HOLDINGS CORP.

      PRIOR TO THE EARLIEST TO OCCUR OF (I)180 DAYS AFTER THE CLOSING OF THE
OFFERING OF THE UNITS, (II) THE DATE ON WHICH A REGISTRATION STATEMENT WITH
RESPECT TO A REGISTERED EXCHANGE OFFER FOR THE NOTES IS DECLARED EFFECTIVE UNDER
THE SECURITIES ACT, (III) THE DATE ON WHICH A REGISTRATION STATEMENT WITH
RESPECT TO THE COMMON STOCK UNDERLYING THE WARRANT IS DECLARED EFFECTIVE UNDER
THE SECURITIES ACT, (IV) SUCH DATE AS CREDIT SUISSE FIRST BOSTON CORPORATION IN
ITS SOLE DISCRETION SHALL DETERMINE AND (V) IN THE EVENT OF THE OCCURRENCE OF A
CHANGE OF CONTROL (AS DEFINED IN THE INDENTURE GOVERNING THE NOTES) THE DATE ON
WHICH THE REQUISITE NOTICE IS MAILED TO HOLDERS OF NOTES, THE NOTES EVIDENCED BY
THIS CERTIFICATE MAY NOT BE TRANSFERRED OR EXCHANGED SEPARATELY FROM, BUT MAY BE
TRANSFERRED OR EXCHANGED ONLY TOGETHER WITH, THE WARRANTS.]

      1. Interest. No interest will accrue on the Notes prior to October 15,
2005. Advanstar, Inc., a Delaware corporation (the "Company"), promises to pay
interest on the principal amount of this Note at 15.0% per annum from October
15, 2005 until maturity. The Company will pay interest semi-annually on April 15
and October 15 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 October 15, 2005; provided that if there is
no 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; and provided further that the first Interest
Payment Date shall be April 15, 2006. The Company shall pay interest (including
post-petition interest in any proceeding under any Bankruptcy Law) on overdue
principal and premium, 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 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 April 1 or October 1 next preceding the Interest
Payment Date, even if

                                     A-2-3
<PAGE>

such Notes are cancelled 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 of the Paying Agent and Registrar. Holders of
Notes must surrender their Notes to the Paying Agent to collect principal
payments, and the Company may pay principal and interest by check and may mail
checks to a Holder's registered address; provided that all payments with respect
to Global Notes and Definitive Notes, the Holders of which have given wire
transfer instructions to the Company, will be required to be made by wire
transfer of immediately available funds to the accounts specified by the Holders
thereof. 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 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 of
February 21, 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 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 initially limited to $171,792,000 in
aggregate principal amount at maturity.

      5. Optional Redemption.

      (a) The Notes will be subject to redemption at any time at the option of
the Company, in whole or in part, upon not less than 30 nor more than 60 days'
notice, in cash at the redemption prices (expressed as percentages of Accreted
Value) equal to 115.000%, if redeemed at any time from the Date of Issuance
until October 15, 2005, and at the redemption prices set forth below, plus
accrued and unpaid interest, if any, thereon to the applicable redemption date,
if redeemed during the twelve-month period beginning on October 15 of the years
indicated below:

               Year                                  Percentage
               ----                                  ----------

               2005..............................    107.500%
               2006..............................    103.750%
               2007..............................    101.875%
               2008 and thereafter...............    100.000%

      (b) Any redemption pursuant to this subparagraph 5 shall be made pursuant
to the provisions of Sections 3.01 through 3.06 of the Indenture.

      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-2-4
<PAGE>

      7. Repurchase at Option of Holder.

      (a) Upon the occurrence of a Change of Control, each Holder of Notes will
have the right to require the Company to repurchase all or any part (equal to
$1,000 principal amount at maturity or an integral multiple thereof) of such
Holder's Notes pursuant to the offer described in Section 4.14 of the Indenture
(the "Change of Control Offer") at an offer price in cash equal to 101% of the
aggregate Accreted Value thereof plus accrued and unpaid interest thereon, if
any, to the date of purchase (the "Change of Control Payment"). Within 60 days
following any Change of Control, the Company will (or will cause the Trustee to)
mail a notice to each Holder describing the transaction or transactions that
constitute the Change of Control and offering to repurchase Notes on the date
specified in such notice, which date shall be no earlier than 30 days and no
later than 60 days from the date such notice is mailed, pursuant to the
procedures required by the Indenture and described in such notice.

      (b) Any Net Proceeds from Asset Sales that are not applied or invested as
provided in Section 4.10 of the Indenture will be deemed to constitute "Excess
Proceeds." When the aggregate amount of Excess Proceeds is greater than $10.0
million, the Company will be required to make an offer to all Holders of Notes
(an "Asset Sale Offer") to purchase the maximum principal amount at maturity 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 Accreted Value thereof, plus accrued and
unpaid interest, if any, thereon to the date of purchase, in accordance with the
procedures set forth in this Indenture. To the extent that any Excess Proceeds
remain after consummation of an Asset Sale Offer, the Company may use such
Excess Proceeds for any purpose not otherwise prohibited by this Indenture. If
the aggregate Accreted Value of Notes surrendered by Holders thereof in
connection with an Asset Sale Offer exceeds the amount of Excess Proceeds, the
Trustee shall select the Notes to be purchased as set forth under Sections 3.02
and 3.03 of the Indenture. Upon completion of such offer to purchase, the amount
of Excess Proceeds shall be reset at zero. Holders of Notes that are the subject
of an offer to purchase may elect to have such Notes purchased by completing the
form entitled "Option of Holder to Elect Purchase" on the reverse of the Notes.

      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 principal amount at maturity may be redeemed in part but only
in whole multiples of $1,000 principal amount at maturity, 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 principal amount at maturity and
integral multiples of $1,000 principal amount at maturity. 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

                                      A-2-5
<PAGE>

exchange or register the transfer of any Note or portion of a Note selected for
redemption, except for the unredeemed portion of any 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 at maturity 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 at maturity of the then outstanding Notes. Without
the consent of any Holder of a Note, 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
materially adversely affect the legal rights under the Indenture of any such
Holders or to comply with the requirements of the Commission in order to effect
or maintain the qualification of the Indenture under the TIA.

      12. Defaults and Remedies. If any Event of Default specified in the
Indenture (other than certain events of bankruptcy or insolvency) occurs and is
continuing, the Holders of at least 25% in principal amount at maturity of the
then outstanding Notes may direct the Trustee to declare the Accreted Value and
accrued and unpaid interest on all the Notes to be due and payable immediately.
Upon any such declaration, the Accreted Value and accrued and unpaid interest on
the Notes shall become due and payable immediately. Notwithstanding the
foregoing, in the case of an Event of Default arising from certain events of
bankruptcy or insolvency, the Accreted Value and accrued and unpaid interest on
all outstanding Notes shall be due and payable immediately without further
action or notice. Holders of the Notes may not enforce the Indenture or the
Notes except as provided in the Indenture. The Holders of a majority in
aggregate principal amount at maturity 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 or interest that has become due solely because of the acceleration)
have been cured or waived; provided that, in the event of a declaration of
acceleration of the Notes because an Event of Default has occurred and is
continuing as a result of the acceleration of any Indebtedness described in
clause (e) of Section 6.01 of the Indenture, the declaration of acceleration of
the Notes shall be automatically annulled if the holders of any Indebtedness
described in clause (e) of Section 6.01of the Indenture have rescinded the
declaration of acceleration in respect of such Indebtedness within 30 days of
the date of such declaration and if (i) the annulment of the acceleration of the
Notes would not conflict with any judgment or decree of a court of competent
jurisdiction and (ii) all existing Events of Default, except non- payment of
principal or interest on the Notes that became due solely because of the

                                      A-2-6
<PAGE>

acceleration of the Notes, have been cured or waived. 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. Additional Rights of Holders of Restricted Global Notes and Restricted
Definitive Notes. In addition to the rights provided to Holders of Notes under
the Indenture, Holders of Restricted Global Notes and Restricted Definitive
Notes shall have all the rights set forth in the Debt Registration Rights
Agreement dated as of February 21, 2001, between the Company and the parties
named on the signature pages thereof (the "Registration Rights Agreement").

      18. 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 and/or the Registration Rights Agreement.
Requests may be made to:

Advanstar, Inc.
545 Boylston Street
9th Floor
Boston, Massachusetts 02110

                                      A-2-7
<PAGE>

Telecopier No.: (617) 267-6900
Attention:  General Counsel

                                      A-2-8
<PAGE>

                                 Assignment Form

To assign this Note, fill in the form below: (I) or (we) assign and transfer
this Note to

(Insert assignee's 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 Note)

                                    Tax Identification No.:_____________________

Signature Guarantee.

                                      A-2-9
<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 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
principal amount at maturity you elect to have purchased: $________

Date:                               Your Signature: ____________________________
                                                    (Sign exactly as your name
                                                    appears on the Note)

                                    Tax Identification No.:_____________________

Signature Guarantee.

                                     A-2-10
<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
                                                                        At Maturity          Signature of
                  Amount of decrease in      Amount of increase       of this Global      authorized officer
                     Principal Amount       in Principal Amount       Note following              of
 Date of               At Maturity               At Maturity           such decrease        Trustee or Note
 Exchange          of this Global Note       of this Global Note       (or increase)          Custodian
 --------         ----------------------    --------------------     ----------------     ------------------
<S>               <C>                        <C>                      <C>                    <C>

</TABLE>

                                     A-2-11
<PAGE>

                                                                       EXHIBIT B

                                 FORM OF CERTIFICATE OF TRANSFER

Telecopier No.:
Attention: General Counsel

Telecopier No.:
Attention:

                  Re: 15.0% Senior Discount Debentures due 2011

      Reference is hereby made to the Indenture, dated as of February 21, 2001
(the "Indenture"), between Advanstar, Inc. (the "Company"), as issuer and Wells
Fargo Bank Minnesota, N.A., as trustee. Capitalized terms used but not defined
herein shall have the meanings given to them in the Indenture.

      ______________ (the "Transferor") owns and proposes to transfer the
Note[s] or interest in such Note[s] specified in Annex A hereto, in the
principal amount at maturity of $___________ in such Note[s] or interests (the
"Transfer"), to __________ (the "Transferee"), as further specified in Annex A
hereto. In connection with the Transfer, the Transferor hereby certifies that:

      [CHECK ALL THAT APPLY]

      1. |_| Check if Transferee will take delivery of a beneficial interest in
the 144A Global Note or a Definitive Note Pursuant to Rule 144A. The Transfer is
being effected pursuant to and in accordance with Rule 144A under the United
States Securities Act of 1933, as amended (the "Securities Act"), and,
accordingly, the Transferor hereby further certifies that the beneficial
interest or Definitive Note is being transferred to a Person that the Transferor
reasonably believed and believes is purchasing the beneficial interest or
Definitive Note for its own account, or for one or more accounts with respect to
which such Person exercises sole investment discretion, and such Person and each
such account is a "qualified institutional buyer" within the meaning of Rule
144A in a transaction meeting the requirements of Rule 144A and such Transfer is
in compliance with any applicable blue sky securities laws of any state of the
United States. Upon consummation of the proposed Transfer in accordance with the
terms of the Indenture, the transferred beneficial interest or Definitive Note
will be subject to the restrictions on transfer enumerated in the Private
Placement Legend printed on the 144A Global Note and/or the Definitive Note and
in the Indenture and the Securities Act.

      2. |_| Check if Transferee will take delivery of a beneficial interest in
the Temporary Regulation S Global Note, the Regulation S Global Note or a
Definitive Note pursuant to Regulation S. The Transfer is being effected
pursuant to and in accordance

                                      B-1
<PAGE>

with Rule 904 under the Securities Act and, accordingly, the Transferor hereby
further certifies that (i) the Transfer is not being made to a Person in the
United States and (x) at the time the buy order was originated, the Transferee
was outside the United States or such Transferor and any Person acting on its
behalf reasonably believed and believes that the Transferee was outside the
United States or (y) the transaction was executed in, on or through the
facilities of a designated offshore securities market and neither such
Transferor nor any Person acting on its behalf knows that the transaction was
prearranged with a buyer in the United States, (ii) no directed selling efforts
have been made in contravention of the requirements of Rule 904(b) of Regulation
S under the Securities Act and (iii) the transaction is not part of a plan or
scheme to evade the registration requirements of the Securities Act. Upon
consummation of the proposed transfer in accordance with the terms of the
Indenture, the transferred beneficial interest or Definitive Note will be
subject to the restrictions on Transfer enumerated in the Private Placement
Legend printed on the Regulation S Global Note, the Temporary Regulation S
Global Note and/or the Definitive Note and in the Indenture and the Securities
Act.

      3. |_| Check and complete if Transferee will take delivery of a beneficial
interest in the IAI Global Note or a Definitive Note pursuant to any provision
of the Securities Act other than Rule 144A or Regulation S. The Transfer is
being effected in compliance with the transfer restrictions applicable to
beneficial interests in Restricted Global Notes and Restricted Definitive Notes
and pursuant to and in accordance with the Securities Act and any applicable
blue sky securities laws of any state of the United States, and accordingly the
Transferor hereby further certifies that (check one):

                  (a) such Transfer is being effected pursuant to and in
            accordance with Rule 144 under the Securities Act;

                                       or

                  (b) such Transfer is being effected to the Company or a
            subsidiary thereof;

                                       or

                  (c) such Transfer is being effected pursuant to an effective
            registration statement under the Securities Act and in compliance
            with the prospectus delivery requirements of the Securities Act;

                                       or

                  (d) such Transfer is being effected to an Institutional
            Accredited Investor and pursuant to an exemption from the
            registration requirements of the Securities Act other than Rule
            144A, Rule 144 or Rule 904, and the Transferor hereby further
            certifies that it has not engaged in any general solicitation within
            the meaning of Regulation D under the Securities Act and the
            Transfer complies with the transfer restrictions applicable to
            beneficial interests in a Restricted Global Note or Restricted
            Definitive Notes and the requirements of the exemption claimed,
            which certification is supported by (1) a certificate executed by
            the Transferee in the form of

                                      B-2
<PAGE>

            Exhibit D to the Indenture and (2) if such Transfer is in respect of
            Notes with Accreted Value at the time of transfer of less than
            $250,000, an Opinion of Counsel provided by the Transferor or the
            Transferee (a copy of which the Transferor has attached to this
            certification), to the effect that such Transfer is in compliance
            with the Securities Act. Upon consummation of the proposed transfer
            in accordance with the terms of the Indenture, the transferred
            beneficial interest or Definitive Note will be subject to the
            restrictions on transfer enumerated in the Private Placement Legend
            printed on the IAI Global Note and/or the Definitive Notes and in
            the Indenture and the Securities Act.

      4. Check if Transferee will take delivery of a beneficial interest in an
Unrestricted Global Note or of an Unrestricted Definitive Note.

      (a) |_| Check if Transfer is pursuant to Rule 144. (i) The Transfer is
being effected pursuant to and in accordance with Rule 144 under the Securities
Act and in compliance with the transfer restrictions contained in the Indenture
and any applicable blue sky securities laws of any state of the United States
and (ii) the restrictions on transfer contained in the Indenture and the Private
Placement Legend are not required in order to maintain compliance with the
Securities Act. Upon consummation of the proposed Transfer in accordance with
the terms of the Indenture, the transferred beneficial interest or Definitive
Note will no longer be subject to the restrictions on transfer enumerated in the
Private Placement Legend printed on the Restricted Global Notes, on Restricted
Definitive Notes and in the Indenture.

      (b) |_| Check if Transfer is Pursuant to Regulation S. (i) The Transfer is
being effected pursuant to and in accordance with Rule 904 under the Securities
Act and in compliance with the transfer restrictions contained in the Indenture
and any applicable blue sky securities laws of any state of the United States
and (ii) the restrictions on transfer contained in the Indenture and the Private
Placement Legend are not required in order to maintain compliance with the
Securities Act. Upon consummation of the proposed Transfer in accordance with
the terms of the Indenture, the transferred beneficial interest or Definitive
Note will no longer be subject to the restrictions on transfer enumerated in the
Private Placement Legend printed on the Restricted Global Notes, on Restricted
Definitive Notes and in the Indenture.

      (c) |_| Check if Transfer is Pursuant to Other Exemption. (i) The Transfer
is being effected pursuant to and in compliance with an exemption from the
registration requirements of the Securities Act other than Rule 144, Rule 904
and in compliance with the transfer restrictions contained in the Indenture and
any applicable blue sky securities laws of any state of the United States and
(ii) the restrictions on transfer contained in the Indenture and the Private
Placement Legend are not required in order to maintain compliance with the
Securities Act. Upon consummation of the proposed Transfer in accordance with
the terms of the Indenture, the transferred beneficial interest or Definitive
Note will not be subject to the restrictions on transfer enumerated in the
Private Placement Legend printed on the Restricted Global Notes or Restricted
Definitive Notes and in the Indenture.

                                      B-3
<PAGE>

      This certificate and the statements contained herein are made for your
benefit and the benefit of the Company.

                                            ____________________________________
                                            [Insert Name of Transferor]

                                            By: ________________________________
                                                Name:
                                                Title:

Dated: __________, ____

                                      B-4
<PAGE>

                       ANNEX A TO CERTIFICATE OF TRANSFER

1.    The Transferor owns and proposes to transfer the following:

                            [CHECK ONE OF (a) OR (b)]

(a)   a beneficial interest in the:

      (i)   |_| 144A Global Note (CUSIP _____________), or

      (ii)  |_| Regulation S Global Note (CUSIP____________), or

      (iii) |_| IAI Global Note (CUSIP _____________), or

(b)   a Restricted Definitive Note.

2.    After the Transfer the Transferee will hold:

                                   [CHECK ONE]

(a)   a beneficial interest in the:

      (i)   |_| 144A Global Note (CUSIP _____________), or

      (ii)  |_| Regulation S Global Note (CUSIP____________), or

      (iii) |_| IAI Global Note (CUSIP _____________), or

      (iv)  |_| Unrestricted Global Note (CUSIP ____________), or

(b)   a Restricted Definitive Note, or

(c)   an Unrestricted Definitive Note, in accordance with the terms of the
      Indenture.

                                      B-5
<PAGE>

                                                                       EXHIBIT C

                         FORM OF CERTIFICATE OF EXCHANGE

Telecopier No.:
Attention: General Counsel

Telecopier No.:
Attention:

                  Re: 15.0% Senior Discount Debentures due 2011

      Reference is hereby made to the Indenture, dated as of February 21, 2001
(the "Indenture"), between Advanstar, Inc. (the "Company"), as issuer, and Wells
Fargo Bank Minnesota, N.A., as trustee. Capitalized terms used but not defined
herein shall have the meanings given to them in the Indenture.

      ____________ (the "Owner") owns and proposes to exchange the Note[s] or
interest in such Note[s] specified herein, in the principal amount at maturity
of $____________ in such Note[s] or interests (the "Exchange"). In connection
with the Exchange, the Owner hereby certifies that:

      1. Exchange of Restricted Definitive Notes or Beneficial Interests in a
Restricted Global Note for Unrestricted Definitive Notes or Beneficial Interests
in an Unrestricted Global Note

      (a) |_| Check if Exchange is from beneficial interest in a Restricted
Global Note to beneficial interest in an Unrestricted Global Note. In connection
with the Exchange of the Owner's beneficial interest in a Restricted Global Note
for a beneficial interest in an Unrestricted Global Note in an equal principal
amount at maturity, the Owner hereby certifies (i) the beneficial interest is
being acquired for the Owner's own account without transfer, (ii) such Exchange
has been effected in compliance with the transfer restrictions applicable to the
Global Notes and pursuant to and in accordance with the United States Securities
Act of 1933, as amended (the "Securities Act"), (iii) the restrictions on
transfer contained in the Indenture and the Private Placement Legend are not
required in order to maintain compliance with the Securities Act and (iv) the
beneficial interest in an Unrestricted Global Note is being acquired in
compliance with any applicable blue sky securities laws of any state of the
United States.

      (b) |_| Check if Exchange is from beneficial interest in a Restricted
Global Note to Unrestricted Definitive Note. In connection with the Exchange of
the Owner's beneficial interest in a Restricted Global Note for an Unrestricted
Definitive Note, the Owner hereby certifies (i) the Definitive Note is being
acquired for the Owner's own account without transfer, (ii) such Exchange has
been effected in compliance with the transfer restrictions applicable to the
Restricted Global Notes and pursuant to and in

                                       C-1
<PAGE>

accordance with the Securities Act, (iii) the restrictions on transfer contained
in the Indenture and the Private Placement Legend are not required in order to
maintain compliance with the Securities Act and (iv) the Definitive Note is
being acquired in compliance with any applicable blue sky securities laws of any
state of the United States.

      (c) |_| Check if Exchange is from Restricted Definitive Note to beneficial
interest in an Unrestricted Global Note. In connection with the Owner's Exchange
of a Restricted Definitive Note for a beneficial interest in an Unrestricted
Global Note, the Owner hereby certifies (i) the beneficial interest is being
acquired for the Owner's own account without transfer, (ii) such Exchange has
been effected in compliance with the transfer restrictions applicable to
Restricted Definitive Notes and pursuant to and in accordance with the
Securities Act, (iii) the restrictions on transfer contained in the Indenture
and the Private Placement Legend are not required in order to maintain
compliance with the Securities Act and (iv) the beneficial interest is being
acquired in compliance with any applicable blue sky securities laws of any state
of the United States.

      (d) |_| Check if Exchange is from Restricted Definitive Note to
Unrestricted Definitive Note. In connection with the Owner's Exchange of a
Restricted Definitive Note for an Unrestricted Definitive Note, the Owner hereby
certifies (i) the Unrestricted Definitive Note is being acquired for the Owner's
own account without transfer, (ii) such Exchange has been effected in compliance
with the transfer restrictions applicable to Restricted Definitive Notes and
pursuant to and in accordance with the Securities Act, (iii) the restrictions on
transfer contained in the Indenture and the Private Placement Legend are not
required in order to maintain compliance with the Securities Act and (iv) the
Unrestricted Definitive Note is being acquired in compliance with any applicable
blue sky securities laws of any state of the United States.

      2. Exchange of Restricted Definitive Notes or Beneficial Interests in
Restricted Global Notes for Restricted Definitive Notes or Beneficial Interests
in Restricted Global Notes.

      (a) |_| Check if Exchange is from beneficial interest in a Restricted
Global Note to Restricted Definitive Note. In connection with the Exchange of
the Owner's beneficial interest in a Restricted Global Note for a Restricted
Definitive Note with an equal principal amount at maturity, the Owner hereby
certifies that the Restricted Definitive Note is being acquired for the Owner's
own account without transfer. Upon consummation of the proposed Exchange in
accordance with the terms of the Indenture, the Restricted Definitive Note
issued will continue to be subject to the restrictions on transfer enumerated in
the Private Placement Legend printed on the Restricted Definitive Note and in
the Indenture and the Securities Act.

      (b) |_| Check if Exchange is from Restricted Definitive Note to beneficial
interest in a Restricted Global Note. In connection with the Exchange of the
Owner's Restricted Definitive Note for a beneficial interest in the [CHECK ONE]
|_| "144A Global Note", |_| "Regulation S Global Note", |_| "IAI Global Note"
with an equal principal amount at maturity, the Owner hereby certifies (i) the
beneficial interest is being acquired for the Owner's own account without
transfer and (ii) such Exchange has been effected in compliance with the
transfer restrictions applicable to the Restricted Global Notes and pursuant to
and in accordance with the Securities Act, and in compliance with any

                                       C-2
<PAGE>

applicable blue sky securities laws of any state of the United States. Upon
consummation of the proposed Exchange in accordance with the terms of the
Indenture, the beneficial interest issued will be subject to the restrictions on
transfer enumerated in the Private Placement Legend printed on the relevant
Restricted Global Note and in the Indenture and the Securities Act.

      This certificate and the statements contained herein are made for your
benefit and the benefit of the Company.

                                            ____________________________________
                                            [Insert Name of Owner]

                                            By: ________________________________
                                                Name:
                                                Title:

Dated: __________, ____

                                       C-3
<PAGE>

                                                                       EXHIBIT D

                            FORM OF CERTIFICATE FROM
                   ACQUIRING INSTITUTIONAL ACCREDITED INVESTOR

Telecopier No.:
Attention: General Counsel

Telecopier No.:
Attention:

                  Re: 15.0% Senior Discount Debentures due 2011

      Reference is hereby made to the Indenture, dated as of February 21, 2001
(the "Indenture"), among Advanstar, Inc. (the "Company"), as issuer, and Wells
Fargo Bank Minnesota, N.A., as trustee. Capitalized terms used but not defined
herein shall have the meanings given to them in the Indenture.

      In connection with our proposed purchase of $________ aggregate principal
amount at maturity of:

      (a) |_| a beneficial interest in a Global Note, or

      (b) |_| a Definitive Note,

we confirm that:

            1. We understand that any subsequent transfer of the Notes or any
      interest therein is subject to certain restrictions and conditions set
      forth in the Indenture and the undersigned agrees to be bound by, and not
      to resell, pledge or otherwise transfer the Notes or any interest therein
      except in compliance with, such restrictions and conditions and the United
      States Securities Act of 1933, as amended (the "Securities Act").

            2. We understand that the offer and sale of the Notes have not been
      registered under the Securities Act, and that the Notes and any interest
      therein may not be offered or sold except as permitted in the following
      sentence. We agree, on our own behalf and on behalf of any accounts for
      which we are acting as hereinafter stated, that if we should sell the
      Notes or any interest therein, we will do so only (A) to the Company or
      any subsidiary thereof, (B) in accordance with Rule 144A under the
      Securities Act to a "qualified institutional buyer" (as defined therein),
      (C) to an institutional "accredited investor" (as defined below) that,
      prior to such transfer, furnishes (or has furnished on its behalf by a
      U.S. broker-dealer) to you and to the Company a signed letter
      substantially in the form of this letter and, if such transfer is in
      respect of Notes with an Accreted Value at the time of

                                       D-1
<PAGE>

      transfer of less than $250,000, an Opinion of Counsel in form reasonably
      acceptable to the Company to the effect that such transfer is in
      compliance with the Securities Act, (D) outside the United States in
      accordance with Rule 904 of Regulation S under the Securities Act, (E)
      pursuant to the provisions of Rule 144(k) under the Securities Act or (F)
      pursuant to an effective registration statement under the Securities Act,
      and we further agree to provide to any person purchasing the Definitive
      Note or beneficial interest in a Global Note from us in a transaction
      meeting the requirements of clauses (A) through (E) of this paragraph a
      notice advising such purchaser that resales thereof are restricted as
      stated herein.

            3. We understand that, on any proposed resale of the Notes or
      beneficial interest therein, we will be required to furnish to you and the
      Company such certifications, legal opinions and other information as you
      and the Company may reasonably require to confirm that the proposed sale
      complies with the foregoing restrictions. We further understand that the
      Notes purchased by us will bear a legend to the foregoing effect. We
      further understand that any subsequent transfer by us of the Notes or
      beneficial interest therein acquired by us must be effected through one of
      the Placement Agents.

            4. We are an institutional "accredited investor" (as defined in Rule
      501(a)(1), (2), (3) or (7) of Regulation D under the Securities Act) and
      have such knowledge and experience in financial and business matters as to
      be capable of evaluating the merits and risks of our investment in the
      Notes, and we and any accounts for which we are acting are each able to
      bear the economic risk of our or its investment.

            5. We are acquiring the Notes or beneficial interest therein
      purchased by us for our own account or for one or more accounts (each of
      which is an institutional "accredited investor") as to each of which we
      exercise sole investment discretion.

      You and the Company are entitled to rely upon this letter and are
irrevocably authorized to produce this letter or a copy hereof to any interested
party in any administrative or legal proceedings or official inquiry with
respect to the matters covered hereby.

                                            ____________________________________
                                            [Insert Name of Accredited Investor]

                                            By: ________________________________
                                                Name:
                                                Title:

Dated: __________, ____

                                       D-2<PAGE>

                                                                   EXHIBIT 4.4

                        UNANIMOUS SHAREHOLDERS AGREEMENT

THIS AGREEMENT Dated For Reference the 1st day of December, 1998

BETWEEN:

          WORLDWIDE FIBER COMMUNICATIONS LTD.

          ("WFCL")

AND:

          LEDCOR INC.

          ("Ledcor")

AND:

          LEDCOR INDUSTRIES LIMITED

          ("LIL")

AND:

          LEDCOM HOLDINGS LTD.

          (the "Corporation")

WHEREAS:

A.   The Corporation is a corporation incorporated under the Act.

B.   WFCL, Ledcor and LIL are the beneficial and registered owners of all the
issued and outstanding shares of the Corporation, holding the following
shares:

          Ledcor, 50 Class "A" Common voting shares;

          LIL, 1,000,000 Class "II" Preference shares; and

          WFCL, 50 Class "A" Common voting shares.

C.   The parties wish to enter into this Agreement for the purpose of
defining certain rights and obligations between each of them and between each
of them and the Corporation.

D.   It is the intent of all of the parties that this Agreement operate and
be construed as a unanimous shareholders agreement for the purposes of the
Act.

IN CONSIDERATION of the mutual agreements in this Agreement and subject to
the terms and conditions specified in this Agreement, the parties agree as
follows:
<PAGE>

                                    ARTICLE 1
                                   DEFINITIONS

1.1  DEFINITIONS

In this Agreement, including the recitals and the schedules, the following
words and expressions have the following meanings unless the context
otherwise requires:

"Act" means the BUSINESS CORPORATIONS ACT, S.A. 1981, c B-15.

"Affiliate" means, with respect to any Shareholder, any body corporate which
is directly or indirectly Controlled by such Shareholder or which Controls
such Shareholder.

"Articles" means the Articles of Incorporation of the Corporation as amended
from time to time.

"Board" means the Board of Directors of the Corporation.

"Bylaws" means any bylaw of the Corporation from time to time in force and
effect.

"Business Day" means a day on which Canadian chartered banks are open for the
transaction of business in Vancouver, British Columbia.

"Change of Control" means and shall be deemed to have occurred:

     (a)  in the case of WFCL, if the individuals who, as of the date of this
          Agreement, constitute the Board of Directors of WFCL, together with
          those individuals who first became directors subsequent to such
          date and whose recommendation, election or nomination for election
          to the Board of Directors of WFCL was approved by Ledcor, cease for
          any reason to constitute a majority of the members of the Board of
          Directors of WFCL; or

     (b)  in the case of Ledcor, if the individuals who, as of the date of
          this Agreement, constitute the Board of Directors of Ledcor,
          together with those who first become directors subsequent to such
          date and whose recommendation, election or nomination for election
          to the Board of Directors of Ledcor was approved by a vote of at
          least a majority of the directors then still in office who either
          were directors as of the date of the Agreement or whose
          recommendation, election or nomination for election was previously
          so approved, cease for any reason to constitute a majority of the
          members of the Board of Directors of Ledcor.

"Control" or "Controlled" means "control" as defined in Section 2 of the Act.

"Directors" means the persons who are from time to time, in accordance with
the terms of this Agreement, duly elected or appointed Directors of the
Corporation.

"Encumber" or "Encumbrance" means any mortgage, pledge, hypothecation or
other encumbrance of shares having the result (directly or indirectly and
either immediately or subject to the happening of any contingency) of
potentially changing the identity of a Shareholder notwithstanding that such
encumbrance shall be voluntary or involuntary on the party of such
Shareholder.

"Escrow Agent" means the Escrow Agent under the Escrow Agreement.

"Escrow Agreement" means the Escrow Agreement described in section 2.7.

"Exercise Notice" has the meaning provided in section 2.3.

                                      -2-
<PAGE>

"Insolvency Event" means the institution of any proceedings or undertaking of
any act to effect the winding up or liquidation of a corporation, the
institution of such proceedings to seek protection from creditors pursuant to
the proposal provisions of the BANKRUPTCY AND INSOLVENCY ACT (Canada), or to
be adjudicated a bankrupt or insolvent under the BANKRUPTCY AND INSOLVENCY
ACT (Canada) or any analagous laws, the consenting to the institution of such
proceedings, the consenting to the filing of any petition under the
BANKRUPTCY AND INSOLVENCY ACT (Canada), or any relief flowing therefrom or
the appointment of a receiver or receiver manager, the institution of any act
or proceeding for the appointment of a receiver or receiver manager, the
making of a general assignment for the benefit of creditors, the seeking of
protection from creditors under the COMPANY CREDITORS ARRANGEMENT ACT, the
admission in writing of insolvency, the passing of a resolution by a
corporation for its winding-up or dissolution, or the dissolution of a
corporation, or the granting of any judgement against the corporation for an
amount exceeding $100,000 if enforcement of such judgement is not stayed
within 15 days of the granting thereof, or the seizure or attempted seizure
of any assets of the corporation by any claimant, including, without
limitation, any share owned by the corporation in the capital of the
Corporation.

"Offending Provision" has the meaning provided in section 8.11.

"Offered Shares" has the meaning provided in subsection 3.2(a).

"Offeree" has the meaning provided in subsection 3.2(a).

"Offeror" has the meaning provided in subsection 3.2(a).

"Option Holder" has the meaning provided in section 2.2.

"Person" means an individual, partnership, corporation (including a business
trust), joint stock company, trust, unincorporated association, joint venture
or other entity or a foreign state or political subdivision thereof or any
agency of such state or subdivision.

"Plough Technology" means the "Rubber Tired Rail Plough" which is the subject
matter of United States patent No. 5,596,822 dated January 28, 1997 and
Canadian patent pending No. 2,131,588, which are owned by the Corporation,
and all information, designs, inventions, discoveries, modifications,
adaptations or improvements relating thereto, all patents, patent
applications, copyrights, integrated circuit topographies, industrial
designs, utility models, proprietary information and other intellectual
property rights, whether tangible or not.

"Purchased Shares" has the meaning provided in section 2.3.

"Shareholders" means collectively WFCL, Ledcor and LIL (or each individually
when the context so requires) and includes all future shareholders who are
deemed to be a party to the Agreement pursuant to the Act.

"Subject Shareholder" has the meaning provided in section 2.1.

"Third Party Offer" has the meaning provided in subsection 3.2(a).

"Transfer" means any transfer, sale, assignment, transmission, bequest,
inheritance, or other disposition of shares having the result (directly or
indirectly and either immediately or subject to the happening of any
contingency) of changing the identity of a shareholder notwithstanding that
such transfer shall be voluntary or involuntary on the part of such
shareholder.

"Transfer Notice" has the meaning provided in subsection 3.2(a).

"Triggering Event" has the meaning provided in section 2.1.

                                      -3-
<PAGE>

1.2  CAPITALIZED WORDS

Capitalized words and phrases used in this Agreement and not defined herein
shall have the same meaning as are assigned to them in the Act.

1.3  REFERENCES TO ENACTMENT

References herein to any enactment of law shall, regardless if there is any
specific reference to an amendment or re-enactment of such law, be deemed in
any event to include reference to (i) such enactment as the same may be
amended or re-enacted from time to time and every statute that may be
substituted therefor, and in the case of any such amendment, re-enactment and
substitution, and reference to such enactment shall be read as referring to
the amended, re-enacted or substituted provisions therefor; and (ii)
regulations and by-laws, if any, made pursuant to such enactment.

                                   ARTICLE 2
                               OPTION TO PURCHASE
                       ON INSOLVENCY OR CHANGE OF CONTROL

2.1  TRIGGERING EVENTS

In this Article 2, a triggering event (the "Triggering Event") shall be
deemed to have occurred in respect of either WFCL or Ledcor (the "Subject
Shareholder") if either of the following events occur:

     (a)  there is a Change of Control of the Subject Shareholder; or

     (b)  the Subject Shareholder commits or is the subject of an Insolvency
          Event or, with respect to Ledcor, LIL commits or is the subject of
          an Insolvency Event.

For the purposes of this Agreement, "Subject Shareholder" includes any
successor in title to WFCL or Ledcor, as the case may be, if any, which
arises either by operation of law or pursuant to the terms of this Agreement.

2.2  OPTION

Notwithstanding any other provision of this Agreement, upon the occurrence of
a Triggering Event in respect of a Subject Shareholder:

     (a)  if the Subject Shareholder is WFCL, then Ledcor (in such case,
          herein called the "Option Holder") will have the option, exercisable
          on or before that day which is six months after the Triggering
          Event, to purchase from the Subject Shareholder all or any part of
          the issued and outstanding shares in the Corporation then held by
          the Subject Shareholder; or

     (b)  if the Subject Shareholder is Ledcor, then WFCL (in such case, herein
          called the "Option Holder") will have the option, exercisable on or
          before that day which is six months after the Triggering Event, to
          purchase from the Subject Shareholder or LIL or both all or any part
          of the issued and outstanding shares in the Corporation then held by
          the Subject Shareholder or LIL or both;

at a purchase price equal to the fair market value of such shares. The fair
market value of such shares will be as determined as follows:

     (c)  If the Triggering Event is a change of control of the Subject
          Shareholder, then the fair market value of such shares sill be
          determined in good faith by agreement between Ledcor and WFCL or,
          in the event that Ledcor and WFCL are for any reason unable to reach
          agreement on the fair market value of the shares within 30 days,
          then Ledcor and WFCL will identify and retain a valuator who is
          accredited as a chartered business valuator for the purposes of
          determining the fair market value of the shares. If Ledcor and WFCL
          fail to agree on the selection of the valuator

                                      -4-
<PAGE>

          within 10 days, then the selection of a valuator shall be referred
          to arbitration under this Agreement. The report of the valuator
          setting out the valuation of the shares will be final and binding on
          the parties.

     (d)  If the Triggering Event is an Insolvency Event, then the Option
          Holder will identify (acting reasonably) and retain a valuator who
          is accredited as a chartered business valuator, for the purpose of
          determining the fair market value of the shares. The valuator shall
          be a person who is dealing at arm's length with the Option Holder.
          The valuator shall render its decision as to the fair market value
          of the shares within 60 days of the valuator's appointment, or such
          longer period of time as may be required by him, acting
          expeditiously, to complete such valuation. The report of the valuator
          setting out the valuation of the shares will be final and binding on
          the parties.

2.3  EXERCISE OF OPTION

The option will be exercisable by the Option Holder delivering to the
Corporation a notice in writing (the "Exercise Notice") exercising the option
which notice must be delivered no later than that day which is six months
after the occurrence of the Triggering Event and which notice must specify
the number and class of shares to be purchased (the "Purchased Shares"). Upon
the giving of the Exercise Notice a binding contract of purchase and sale
between the Option Holder and the Subject Shareholder (and LIL, as the case
may be) will be deemed to come into existence on the terms specified in this
Agreement.

2.4  CLOSING

The closing of the purchase and sale of the Purchased Shares shall take place
at the head office of the Corporation on a closing date to be determined by
the Option Holder, provided that the closing date shall not be later than the
day which is 60 days after the determination of the purchase price. At the
closing, each of the parties shall execute and deliver to the others such
documents and instruments and take such further actions as may be necessary
or appropriate to effect the transfer of the Purchased Shares to the Option
Holder, and the Option Holder will pay the purchase price for the Purchased
Shares.

2.5  SUBJECT SHAREHOLDER DEFAULT

If the Subject Shareholder (or LIL, as the case may be) refuses or fails to
execute the documents and instruments necessary to transfer the Purchased
Shares to the Option Holder, on tender of payment of the price for the
Purchased Shares, the Subject Shareholder (or LIL, as the case may be) will
be bound to transfer those shares to the Option Holder and, if the Subject
Shareholder (or LIL, as the case may be) fails to do so, the Corporation will
cause the name of the Option Holder to be entered into the register of
members of the Corporation as the holder of those shares and will cancel the
share certificates previously issued to the Subject Shareholder (or LIL, as
the case may be) representing those shares, whether they have been produced
to the Corporation or not. Payment to the Corporation, as agent for the
Subject Shareholder (or LIL, as the case may be), of the purchase price will
be sufficient payment by the Option Holder and entry of the transfers in the
register of members of the Corporation will be conclusive evidence of the
validity of the transfers. Upon completion of the transfers, and delivery of
the share certificates duly endorsed in blank for transfer, the Corporation
will pay the purchase price to the Subject Shareholder.

2.6  SECURITY INTEREST

In support of the obligations of the parties under this Article 2:

     (a)  WFCL hereby delivers to the Escrow Agent, as agent for Ledcor, the
          share certificates representing all the issued and outstanding shares
          of the corporation held by WFCL and hereby grants to Ledcor a security
          interest in such shares and all proceeds of such shares (including,
          without limitation, all stock certificates, options, or rights of
          any nature whatsoever which may be issued or granted in respect of
          such shares, and all dividends or other income, collections thereon
          or distributions with respect thereto), as collateral security for
          the prompt and complete

                                      -5-
<PAGE>

          performance when due of all obligations of WFCL under this Article
          2 (the "Secured Obligations"). If WFCL shall, as a result of its
          ownership of such shares, become entitled to receive or shall
          receive any stock certificate (including, without limitation, any
          certificate representing a stock dividend or distribution in
          connection with any reclassification, increase or redemption of
          capital or any certificate issued in connection with any
          reorganization), option or rights, whether in addition to, in
          substitution of, as a conversion of, or in exchange for any shares
          which are pledged hereunder, or otherwise in respect thereof, WFCL
          shall accept the same as agent for Ledcor, hold the same in trust
          for Ledcor and deliver the same forthwith to the Escrow Agent, as
          agent for Ledcor, in the exact form received and, at the option of
          Ledcor, duly endorsed by WFCL in blank or accompanied by an undated
          stock power or other instrument of transfer reasonably acceptable
          to Ledcor covering such certificate duly executed in blank by WFCL,
          as additional collateral security for the Secured Obligations. In
          case any distribution of capital should be made on or in respect of
          any such shares, or any property shall be distributed  upon or with
          respect to such shares,  pursuant to the recapitalization or
          reclassification of the capital of the corporation or pursuant to
          the reorganization thereof, the property so distributed shall be
          delivered to the Escrow Agent, as agent for Ledcor, to be held by
          it under the Escrow Agreement as additional collateral security for
          the Secured Obligations. If any property so paid or distributed
          shall be received by WFCL, WFCL shall, until such property is paid
          or delivered to the Escrow Agent, hold such property in trust for
          Ledcor, as additional collateral security for the Secured
          Obligations.

     (b)  Ledcor and LIL each hereby delivers to the Escrow Agent, as agent
          for WFCL, the share certificates representing all the issued and
          outstanding shares of the corporation held by Ledcor and LIL and
          each hereby grants to WFCL a security interest in such shares all
          proceeds of such shares (including, without limitation, all stock
          certificates, options, or rights of any nature whatsoever which may
          be issued or granted in respect of such shares, and all dividends
          or other income, collections thereon or distributions with respect
          thereto), as collateral security for the prompt and complete
          performance when due of all obligations of Ledcor and LIL under
          this Article 2 (the "Secured Obligations"). If Ledcor or LIL shall,
          as a result of its ownership of such shares, become entitled to
          receive or shall receive any stock certificate (including, without
          limitation, any certificate representing a stock dividend or
          distribution in connection with any reclassification, increase or
          redemption of capital or any certificate issued in connection with
          any reorganization), option or rights, whether in addition to, in
          substitution of, as a conversion of, or in exchange for any shares
          which are pledged hereunder, or otherwise in respect thereof,
          Ledcor or LIL, as the case may be, shall accept the same as agent
          for WFCL, hold the same in trust for WFCL and deliver the same
          forthwith to the Escrow Agent, as agent for WFCL, in the exact form
          received and, at the option of WFCL, duly endorsed by Ledcor or
          LIL, as the case may be, in blank or accompanied by an undated
          stock power or other instrument of transfer reasonably acceptable
          to WFCL covering such certificate duly executed in blank by Ledcor
          or LIL, as the case may be, as additional collateral security for
          the Secured Obligations. In case any distribution of capital should
          be made on or in respect of any such shares, or any property shall
          be distributed upon or with respect to such shares, pursuant to the
          recapitalization or reclassification of the capital of the
          corporation or pursuant to the reorganization thereof, the property
          so distributed shall be delivered to the Escrow Agent, as agent for
          WFCL, to be held by it under the Escrow Agreement as additional
          collateral security for the Secured Obligations. If any property so
          paid or distributed shall be received by Ledcor or LIL, Ledcor or
          LIL, as the case may be, shall, until such property is paid or
          delivered to the Escrow Agent, hold such property in trust for
          WFCL, as additional collateral security for the Secured Obligations.

2.7  ESCROW AGREEMENT

As further security for the performance of the obligations of the parties
under this Article 2, Ledcor, LIL and WFCL will execute an Escrow Agreement,
and deliver to the Escrow Agent under the Escrow Agreement the share
certificates representing the shares which they hold in the Corporation.

                                      -6-
<PAGE>

                                    ARTICLE 3
                            RESTRICTIONS ON TRANSFER

3.1  RESTRICTION ON TRANSFER

No Shareholder will Transfer all or any part of its shares to any Person,
whether a Shareholder or not, except as otherwise expressly provided in this
Agreement.

3.2  RIGHT OF FIRST REFUSAL

     (a)  A Shareholder (the "Offeror") desiring to transfer any or all of its
          shares will give written notice to the Corporation (the "Transfer
          Notice") specifying the number of its shares that it desires to
          Transfer (the "Offered Shares"), the price, in lawful money of
          Canada, for the Offered Shares, and the terms of payment upon which
          the Offeror is prepared to transfer the Offered Shares. The
          Transfer Notice will constitute the Corporation as the agent of the
          Offeror for the sale of the Offered Shares to Ledcor, if the
          Offeror is WFCL, or to WFCL if the Offeror is Ledcor or LIL (Ledcor
          or WFCL, as the case may be, is herein called the "Offeree"), at
          the price and upon the terms of payment specified in the Transfer
          Notice. The Transfer Notice will also state whether the Offeror has
          received an offer to purchase (the "Third Party Offer") the Offered
          Shares, or any of them, from, or proposes to sell the Offered
          Shares, or any of them, to, any particular Person or Persons who
          are not Shareholders and, if so, the names and addresses of those
          Persons and the price and terms in the Third Party Offer will be
          specified in the Transfer Notice. The Transfer Notice will
          constitute an offer by the Offeror to the Offeree to sell all, but
          not less than all, of the Offered Shares to the Offeree and will
          not be revocable.

     (b)  Upon the Corporation's receipt of a written notice of acceptance
          from the Offeree to purchase all the Offered Shares, a binding
          contract of purchase and sale between the Offeror and the Offeree
          will be deemed to come into existence on the terms set out in this
          Agreement and the Transfer Notice.

     (c)  On tender of payment of the price for the Offered Shares, the
          Offeror will be bound to transfer those shares to the Offeree and
          if the Offeror fails to do so the Corporation will cause the name
          of the Offeree to be entered in the register of members of the
          Corporation as the holder of those shares and will cancel the share
          certificates previously issued to the Offeror representing those
          shares whether they have been produced to the Corporation or not.
          Payment to the Corporation, as agent for the Offeror, of the
          purchase price will be sufficient payment by the Offeree and entry
          of the transfers in the register of members of the Corporation will
          be conclusive evidence of the validity of the transfers. Upon
          completion of the transfers, and delivery of the share certificates
          duly endorsed in blank for transfer, the Corporation will pay the
          purchase price to the Offeror.

     (d)  The Offeror may for a period of 60 days after the expiration of the
          30-day period provided for in subsection (b) above transfer to any
          person the Offered Shares pursuant to subsections (b) and (c) above,
          provided that:

          (i)    the Offeror may not sell less than all the Offered Shares;

          (ii)   the Offeror will sell the Offered Shares for cash at closing,
                 free and clear of encumbrances, and on terms which are
                 otherwise identical to those specified in the Transfer Notice;

          (iii)  the Offeror will not sell any of the Offered Shares to any
                 Person, unless at the time of the sale that Person complies
                 with section 3.4; and

          (iv)   if the Offeror has not transferred the Offered Shares or any
                 of them within the 90-day period, then the provisions of this
                 section 3.2 will again become applicable to all of the
                 Offered Shares not disposed of within the 90-day period.

                                      -7-
<PAGE>

     (e)  The provisions as to transfers of shares contained in subsections
          (a), (b), (c) and (d) of this section 3.2 will not apply:

          (i)   if, before the proposed transfer of shares is made, the
                Offeree waives its right to receive the Transfer Notice; or

          (ii)  to any transfer of shares pursuant to the provisions of
                Article 2 of this Agreement.

3.3  NO TRANSFER BY SUBJECT SHAREHOLDER

If a Shareholder is or has been a Subject Shareholder under section 2.2 (or,
in the case of LIL, Ledcor is or has been a Subject Shareholder under section
2.2), then notwithstanding any other provision of this Agreement, except as
required by the terms of this Agreement, such Shareholder will not be
entitled to Transfer or otherwise dispose of its shares, or any part thereof,
without the prior written consent of the other Shareholders during the
applicable six month period after the occurrence of the Triggering Event
under section 2.1.

3.4  FURTHER RESTRICTION OF TRANSFER

No Shareholder will Transfer all or any part of its shares to any Person,
whether a Shareholder or not, who is not a party to or has not agreed to be
bound by this Agreement until such Person agrees in writing to be bound by
this Agreement. The Shareholders and the Corporation will not recognize or
treat as a shareholder of the Corporation any Person who acquires any
interest or control over any shares or afford any such Person the rights
afforded by this Agreement or any of the incidents connected with being a
shareholder of the Corporation until such Person subscribes to or agrees to
be bound by this Agreement, and the Shareholders need only deal with, as a
shareholder of the Corporation, Persons who agree in writing to be bound by
this Agreement.

                                   ARTICLE 4
                         AGREEMENT ON CORPORATE MATTERS

4.1  CORPORATE MATTERS

The Shareholders and the Corporation agree that, notwithstanding any
provisions to the contrary contained in the Articles of the Corporation, the
corporate matters referred to in this Article 4 will be governed by the
applicable provisions of this Article 4, and that in the case of any
inconsistency or conflict between the Articles of the Corporation and the
provisions of this Article 4, the provisions of this Article 4 will govern.

4.2  DIRECTORS

The Shareholders will vote their shares so that the Board comprises of six
Directors, which include three nominees of WFCL and three nominees of Ledcor.
Subject to the foregoing, if a position on the Board formerly held by a
director is open for any reason, the Shareholder whose nominee formerly
occupied such position will be entitled to nominate a new director to fill
the vacancy. The initial directors nominated by Ledcor shall be David Lede,
Clifford Lede and Ronald Stevenson. The initial directors nominated by WFCL
shall be John Manrusiak, Larry Olsen and Stephen Stow.

4.3  FAILURE TO VOTE

In the event that a director fails to vote and act as a director to carry out
the provisions of this Agreement, the Shareholders will exercise their rights
as shareholders of the Corporation to remove such director from the Board
and, subject to section 4.2, to elect in his or her place an individual who
will use his or her best efforts to carry out the provisions of this
Agreement.

                                      -8-
<PAGE>

4.4  MATTERS REQUIRING APPROVAL OF LEDCOR AND WFCL

No sale, license, lease, transfer, mortgage, pledge or other disposition of
all or any part of the Plough Technology will be undertaken without the prior
written consent in writing of both of Ledcor and WFCL.

                                   ARTICLE 5
                    ARTICLES AND IMPLEMENTATION OF AGREEMENT

5.1  ARTICLES AND BYLAWS

The Articles and Bylaws shall at all times be subject to this Agreement and
where any provision of the Articles or Bylaws is inconsistent with this
Agreement, this Agreement shall prevail. Subject to the jurisdiction of the
Court of Queen's Bench of Alberta, any Shareholder may require all of the
Shareholders to cause the Articles or Bylaws to be amended or altered to the
extent necessary to remove or correct such inconsistency.

5.2  VOTING OF SHARES

Each of the Shareholders shall vote or cause to be voted the shares owned by
it in such a way so as to fully implement the terms and conditions of this
Agreement and shall, if any director for any reason refuses to exercise his
discretion in accordance with the terms of this Agreement, forthwith take
such steps as are necessary to remove such director notwithstanding any
provision contained herein to the contrary.

5.3  CONSENTS TO TRANSFERS

Each of the Shareholders shall be deemed to have consented to any transfer of
shares made in accordance with this Agreement and each Shareholder covenants
and agrees to waive any restriction on transfer contained in the Articles or
Bylaws in order to give effect to such transfer.

5.4  ACKNOWLEDGEMENT BY CORPORATION

The Corporation, by its execution hereof, hereby acknowledges that it has
actual notice of the terms of this Agreement, consents thereto and hereby
covenants with each of the Shareholders that it will at all times during the
continuance hereof, be governed by this Agreement in carrying out its
business and affairs and accordingly, shall give or cause to be given such
notices, execute or cause to be executed such deeds, transfers and documents
and do or cause to be done all such acts, matters and things as may from time
to time be necessary or conducive to the carrying out of the terms and intent
hereof.

                                   ARTICLE 6
                             RESTRICTIONS ON SHARES

6.1  SHARE CERTIFICATE ENDORSEMENT

The certificates representing the shares of the Corporation shall be endorsed
with the following reference as to the restrictions imposed by this Agreement:

          "The shares represented by this Certificate are subject to the
          provisions of the Unanimous Shareholders Agreement made on the
          1st day of December, 1998, among the Corporation and all of
          the shareholders, which agreement imposes restrictions on the
          right of a shareholder, and successors of a shareholder, to
          sell, encumber, realize or otherwise deal with the shares
          represented hereby and notice of the terms and conditions of
          the Unanimous Shareholders Agreement is hereby given. A copy
          of the Unanimous Shareholders Agreement may be viewed at the
          registered office of the Corporation."

                                      -9-
<PAGE>

6.2  RESTRICTIONS ON TRANSFERS AND ENCUMBRANCES

     Each of the Shareholders covenants and agrees that:

     (a)  a Shareholder shall not Encumber its shares, or any part thereof;

     (b)  a Shareholder shall not Transfer its shares, or any part thereof,
          except for a Transfer made strictly in accordance with the terms
          of this Agreement; and

     (c)  a Transfer or Encumbrance of all or any part of a Shareholder's
          shares shall be void and without effect unless the Transfer or
          Encumbrance is made strictly in accordance with the terms of this
          Agreement and the transferee or encumbrancee as the case may be,
          first agrees in writing to be bound by the terms of this Agreement
          in the place and stead of the Shareholder.

6.3  BENEFICIAL OWNERSHIP

Each of the Shareholders hereby represents and warrants to the other
Shareholders and the Corporation that as of the date of this Agreement all of
the issued shares of the capital stock of the Corporation owned by such
Shareholders are owned both legally and beneficially solely by them.

                                   ARTICLE 7
                        UNANIMOUS SHAREHOLDERS AGREEMENT

7.1  UNANIMOUS SHAREHOLDERS AGREEMENT

This Agreement is deemed be a unanimous shareholders agreement and is subject
to the provisions relating to unanimous shareholders agreements contained in
the Act.

                                   ARTICLE 8
                                    GENERAL

8.1  ARBITRATION

All disputes arising out of or in connection with this Agreement, or in
respect of any defined legal relationship associated therewith or derived
therefrom, will be referred to and finally resolved by arbitration under the
Rules of the British Columbia International Commercial Arbitration Centre.
The appointing authorities will be the British Columbia International
Commercial Arbitration Centre. The case will be administered by the British
Columbia International Commercial Arbitration Centre in accordance with its
"Procedures for Cases Under the BCICAC Rules". The place of arbitration will
be Vancouver, British Columbia, Canada.

8.2  GOVERNING LAW AND ATTORNMENT

This Agreement will be governed by and construed in accordance with the
substantive laws of Alberta and the federal laws of Canada applicable in
Alberta, without regard to the conflict of law rules of Alberta. Subject to
section 8.1, the parties irrevocably submit to and accept generally and
unconditionally the exclusive jurisdiction of the courts and appellate courts
of Alberta with respect to any legal action or proceeding which may be
brought at any time relating in any way to this Agreement. Each of the
parties irrevocably waives any objection it may now or in the future have to
the venue of any such action or proceeding, and any claim it may now or in
the future have that any such action or proceeding has been brought in an
inconvenient forum.

8.3  TIME OF THE ESSENCE OF THE AGREEMENT

Unless otherwise specifically provided in this Agreement, time will be of the
essence of this Agreement and of the transactions contemplated by this
Agreement.

                                      -10-
<PAGE>

8.4  REMEDIES NOT EXCLUSIVE

The remedies provided to the parties under this Agreement are cumulative and
not exclusive to each other, and any such remedy will not be deemed or
construed to affect any right which any of the parties is entitled to seek at
law, in equity or by statute.

8.5  NOTICES

Any notice, direction, request or other communication required or
contemplated by any provision of this Agreement will be given in writing and
will be given by delivering or faxing same to the parties as follows:

     (a)  To WFCL at:

          Suite 1510 - 1066 West Hastings Street
          Vancouver, British Columbia
          V6E 3X1

          Attention:        Mr. Stephen Stow
          Fax No.:          (604) 681-6822

     (b)  To Ledcor or LIL at:

          Suite 1000 - 1066 West Hastings Street
          Vancouver, British Columbia  V6E 2X1

          Attention:        Mr. David Lede
          Fax No.:          (604) 681-1606

     (c)  To the Corporation at:

          Ledcor Industries Limited
          Suite 1000 - 1066 West Hastings Street
          Vancouver, British Columbia  V6E 2X1

          Attention:        Mr. David Lede
          Fax No.:          (604) 681-1606

          with a copy to:

          Suite 1510 - 1066 West Hastings Street
          Vancouver, British Columbia  V6E 3X1

          Attention:        Mr. Stephen Stow
          Fax No.:          (604) 681- 6822

Any such notice, direction, request or other communication will be deemed to
have been given or made on the date on which it was delivered or, in the case
of fax, on the next business day after receipt of transmission. Any party may
change its fax number or address for service from time to time by written
notice in accordance with this section.

8.6  COUNTERPARTS

This Agreement may be executed in any number of counterparts with the same
effect as if all parties had signed the same document. All of these
counterparts will for all purposes constitute one agreement, binding on the
parties, notwithstanding that all parties are not signatories to the same
counterpart. A fax transcribed copy or photocopy of

                                      -11-
<PAGE>

this Agreement executed by a party in counterpart or otherwise will
constitute a properly executed, delivered and binding agreement or
counterpart of the executing party.

8.7  WAIVER

No failure or delay on the part of any party in exercising any power or right
under this Agreement will operate as a waiver of such power or right. No
single or partial exercise of any right or power under this Agreement will
preclude any further or other exercise of such right or power. No
modification or waiver of any provision of this Agreement and no consent to
any departure by any party from any provision of this Agreement will be
effective until the same is in writing. Any such waiver or consent will be
effective only in the specific instance and for the specific purpose for
which it was given. No notice to or demand on any party in any circumstances
will entitle such party to any other or further notice or demand in similar
or other circumstances.

8.8  FURTHER ASSURANCES

Each of the parties will promptly execute and deliver to the other at the
cost of the other such further documents and assurances and take such further
actions as the other may from time to time request in order to more
effectively carry out the intent and purpose of this Agreement and to
establish and protect the rights, interests and remedies intended to be
created in favour of the other.

8.9  ENTIRE AGREEMENT

This Agreement and any documents and agreements to be delivered pursuant to
this Agreement supersede all previous invitations, proposals, letters,
correspondence, negotiations, promises, agreements, covenants, conditions,
representations and warranties with respect to the subject matter of this
Agreement. There is no representation, warranty, collateral term or condition
or collateral agreement affecting this Agreement, other than as expressed in
writing in this Agreement.

8.10 AMENDMENTS

No change or modification of this Agreement will be valid unless it is in
writing and signed by each party to this Agreement.

8.11 INVALIDITY OF PARTICULAR PROVISION

If any provision of this Agreement or any part of any provision (in this
section called the "Offending Provision") is declared or becomes
unenforceable, invalid or illegal for any reason whatsoever including,
without limiting the generality of the foregoing, a decision by any competent
courts, legislation, statutes, bylaws or regulations or any other
requirements having the force of law, then the remainder of this Agreement
will remain in full force and effect as if this Agreement had been executed
without the Offending Provision.

8.12 CURRENCY

Unless otherwise specified all sums of money expressed in this Agreement are
in the lawful money of Canada.

8.13 NUMBER AND GENDER

Unless the context of this Agreement otherwise requires, to the extent
necessary so that each clause will be given the most reasonable
interpretation, the singular number will include the plural and vice versa,
the verb will be construed as agreeing with the word so substituted, words
importing the masculine gender will include the feminine and neuter genders,
words importing persons will include firms and corporations and words
importing firms and corporations will include individuals.

                                      -12-
<PAGE>

8.14 HEADINGS AND CAPTIONS

The headings and captions of sections and paragraphs contained in this
Agreement are all inserted for convenience of reference only and are not to
be considered when interpreting this Agreement.

8.15 ACKNOWLEDGEMENT OF RECEIPT

Each of the parties acknowledges receiving an executed copy of this Agreement.

8.16 ENUREMENT

Subject to the restrictions on transfer contained in this Agreement, this
Agreement will enure to the benefit of and be binding on the parties and
their respective heirs, executors, administrators, successors and assigns.

IN WITNESS WHEREOF the parties have executed this Agreement on the dates
stated below.

WORLDWIDE FIBER COMMUNICATIONS LTD.         LEDCOR INC.

Per: Signed                                 Per: Signed

----------------------------------          ----------------------------------
Signature                                   Signature

----------------------------------          ----------------------------------
Name                                        Name

----------------------------------          ----------------------------------
Title                                       Title

December 1, 1998                            December 1, 1998
----------------------------------          ----------------------------------
Date of Execution                           Date of Execution

LEDCOM HOLDINGS LTD.                        LEDCOR INDUSTRIES LIMITED

Per: Signed                                 Per: Signed

----------------------------------          ----------------------------------
Signature                                   Signature

----------------------------------          ----------------------------------
Name                                        Name

----------------------------------          ----------------------------------
Title                                       Title

December 1, 1998                            December 1, 1998
----------------------------------          ----------------------------------
Date of Execution                           Date of Execution

                                      -13-

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