<PAGE>   1
                                                                     EXHIBIT 4.1




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                             BECKMAN COULTER, INC.,

                                    AS ISSUER

                 COULTER CORPORATION AND HYBRITECH INCORPORATED,

                                  AS GUARANTORS

                                       AND

                                 CITIBANK, N.A.

                                   AS TRUSTEE

                    ----------------------------------------


                          FIRST SUPPLEMENTAL INDENTURE

                           Dated as of June ___, 2001


                    ----------------------------------------


                 Supplemental to Senior Indenture dated as of April 25, 2001



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<PAGE>   2

                                TABLE OF CONTENTS


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<S>               <C>                                                                     <C>
                                          ARTICLE I

                   DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

SECTION 101.      Definitions...............................................................2
SECTION 102.      Conflicts with Base Indenture............................................22

                                          ARTICLE II

                                        FORM OF NOTES

SECTION 201.      Form of Notes............................................................22

                                         ARTICLE III

                                          THE NOTES

SECTION 301.      Title and Terms..........................................................22
SECTION 302.      Registrar, Paying Agent and Conversion Agent.............................23
SECTION 303.      Purchase of Notes at Option of the Company; Notice to Trustee............23
SECTION 304.      Selection of Notes to be Redeemed........................................24
SECTION 305.      Notice of Redemption.....................................................24
SECTION 306.      Effect of Notice of Redemption...........................................25
SECTION 307.      Deposit of Redemption Price..............................................26
SECTION 308.      Notes Redeemed in Part...................................................26
SECTION 309.      Conversion Arrangement on Call for Redemption............................26
SECTION 310.      Purchase of Notes at Option of the Holder................................27
SECTION 311.      Repurchase of Notes at Option of the Holder upon Fundamental Change......33
SECTION 312.      Effect of Purchase Notice or Fundamental Change Repurchase Notice........41
SECTION 313.      Deposit of Purchase Price or Fundamental Change Repurchase Price.........42
SECTION 314.      Notes Purchased or Repurchased in Part...................................43
SECTION 315.      Covenant to Comply with Securities Laws upon Purchase or Repurchase of
                  Notes....................................................................43
SECTION 316.      Repayment to the Company.................................................44

                                          ARTICLE IV

                                 SPECIAL TAX EVENT CONVERSION

SECTION 401.      Optional Conversion to Semi-Annual Cash Pay Note Upon Tax Event..........44
SECTION 402.      Paying Agent to Hold Money in Trust......................................45
SECTION 403.      Holder Lists.............................................................45
SECTION 404.      Payment of Interest; Interest Rights Preserved...........................45
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                                TABLE OF CONTENTS
                                   (CONTINUED)


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                                          ARTICLE V

                                          CONVERSION

SECTION 501.      Conversion Privilege.....................................................46
SECTION 502.      Conversion Procedure.....................................................48
SECTION 503.      Fractional Shares........................................................49
SECTION 504.      Taxes on Conversion......................................................49
SECTION 505.      Company to Provide Stock.................................................49
SECTION 506.      Adjustment for Change in Capital Stock...................................50
SECTION 507.      Adjustment for Rights Issue..............................................51
SECTION 508.      Adjustment for Other Distributions.......................................52
SECTION 509.      When Adjustment May be Deferred..........................................53
SECTION 510.      When No Adjustment Required..............................................54
SECTION 511.      Notice of Adjustment.....................................................54
SECTION 512.      Voluntary Increase.......................................................54
SECTION 513.      Notice of Certain Transactions...........................................55
SECTION 514.      Reorganization of Company; Special Distributions.........................55
SECTION 515.      Company Determination Final..............................................56
SECTION 516.      Trustee's Adjustment Disclaimer..........................................56
SECTION 517.      Simultaneous Adjustments.................................................56
SECTION 518.      Successive Adjustments...................................................56
SECTION 519.      Rights Issued in Respect of Common Stock Issued Upon Conversion..........56

                                          ARTICLE VI

                                    COVENANTS AND REMEDIES

SECTION 601.      Maintenance of Properties................................................57
SECTION 602.      Payment of Taxes and Other Claims........................................57
SECTION 603.      Limitation on Liens......................................................57
SECTION 604.      Limitation on Sale and Leaseback Transactions............................58
SECTION 605.      Limitation on Incurrence of Indebtedness.................................59
SECTION 606.      Limitation on Restricted Payments........................................59
SECTION 607.      Provision of Financial Statements and Reports............................61
SECTION 608.      Future Note Guarantors...................................................61
SECTION 609.      Additional Limitations on Consolidation, Etc.............................61
SECTION 610.      Additional Events of Default.............................................62
SECTION 611.      Acceleration of Maturity; Rescission and Annulment.......................64
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                                       ii
<PAGE>   4

                                TABLE OF CONTENTS
                                   (CONTINUED)


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                                         ARTICLE VII

                                     THE NOTE GUARANTEES

SECTION 701.      Unconditional Guarantee..................................................65
SECTION 702.      Additional Note Guarantors...............................................67
SECTION 703.      Release of a Note Guarantee..............................................67
SECTION 704.      Waiver of Subrogation....................................................67
SECTION 705.      Reliance on Judicial Order or Certificate of Liquidating Agent Regarding
                  Dissolution..............................................................68
SECTION 706.      Article VII Applicable to Paying Agents..................................68
SECTION 707.      No Suspension of Remedies................................................68

                                         ARTICLE VIII

                                        MISCELLANEOUS

SECTION 801.      Sinking Funds............................................................69
SECTION 802.      Defeasance and Covenant Defeasance.......................................69
SECTION 803.      Confirmation of Indenture................................................69
SECTION 804.      Counterparts.............................................................69
SECTION 805.      Governing Law............................................................69

EXHIBIT A         Form of Note.............................................................A-1
EXHIBIT B         Form of Purchase Notice..................................................B-1
EXHIBIT C         Form of Fundamental Change Repurchase Notice.............................C-1
EXHIBIT D         Form of Supplemental Indenture in respect of Note Guarantee..............D-1
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                                       iii
<PAGE>   5

               FIRST SUPPLEMENTAL INDENTURE, dated as of June ___, 2001 (this
"Supplemental Indenture"), among Beckman Coulter, Inc., a corporation duly
organized and existing under the laws of the State of Delaware (the "Company"),
Coulter Corporation, a corporation duly organized and existing under the laws of
the State of Delaware, Hybritech Incorporated, a corporation duly organized and
existing under the laws of the State of California (the "Guarantors") and
Citibank, N.A., a national banking association duly organized and existing under
the laws of the United States of America, as Trustee (the "Trustee") under the
Senior Indenture dated as of April 25, 2001 between the Company and the Trustee
(the "Base Indenture").

               WHEREAS, Section 901 (7) of the Base Indenture provides that the
Company and Trustee, at any time and from time to time, may enter into one or
more indentures supplemental to the Base Indenture to establish the form or
terms of Securities of any series as permitted by Sections 201 and 301 thereof;

               WHEREAS, the Base Indenture also provides for the issuance from
time to time of unsecured senior debentures, notes or other evidences of
indebtedness (the "Securities");

               WHEREAS, the Company has duly authorized the creation of a Series
of its Securities denominated as the "Zero Coupon Convertible Senior Notes Due
2021" (the "Notes");

               WHEREAS, the Guarantors are executing this Supplemental Indenture
pursuant to which the Guarantors will guarantee the Company's obligations under
the Notes on the terms and conditions set forth herein;

               WHEREAS, the entry into this Supplemental Indenture by the
parties hereto is in all respects authorized by the provisions of the Base
Indenture; and

               WHEREAS, the Company has duly authorized the execution and
delivery of this Supplemental Indenture, to establish the Notes as provided for
in this Supplemental Indenture, and to make this Supplemental Indenture a valid
agreement of the Company, in accordance with their and its terms:

               NOW, THEREFORE, for and in consideration of the premises and
purchase of the Notes issued on or after the date of this Supplemental Indenture
by the Holders thereof, it is mutually covenanted and agreed, for the equal and
proportionate benefit of all Holders of the Notes, as follows:

<PAGE>   6

                                    ARTICLE I

                       DEFINITIONS AND OTHER PROVISIONS OF
                               GENERAL APPLICATION

SECTION 101. Definitions.

               For all purposes of this Supplemental Indenture, except as
otherwise expressly provided or unless the context otherwise requires:

               (1) the words "herein", "hereof" and "hereunder" and other words
of similar import refer to the Indenture as a whole and not to any particular
Article, Section or other subdivision;

               (2) capitalized terms used but not defined herein are used as
they are defined in the Base Indenture; and

               (3) the following terms have the specified meanings:

               "Accreted Conversion Price" has the meaning specified in Section
501 of this Supplemental Indenture.

               "Acquired Debt" means (1) Indebtedness of any Person (the
"Acquired Person") existing at the time the Acquired Person merges or
consolidates with or into, or becomes a Restricted Subsidiary of, the Company or
any Restricted Subsidiary, or (2) Indebtedness of any Person assumed by the
Company or any Restricted Subsidiary in connection with its acquisition of
assets from such Person, in each case excluding Indebtedness incurred in
connection with, or in contemplation of, the Acquired Person merging or
consolidating with or into, or becoming a Restricted Subsidiary of, the Company
or any Restricted Subsidiary, or such acquisition of assets.

               "Acquiring Person" has the meaning specified in Section 311 of
this Supplemental Indenture.

               "Acquisition" means the acquisition by the Company of all of the
capital stock of Coulter Corporation on October 31, 1997.

               "Affiliate" of any specified Person means any other Person,
directly or indirectly, controlling or controlled by or under direct or indirect
common control with such specified Person. For the 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.

               "Asset Sale" means (1) any sale, lease, conveyance or other
disposition by the Company or any Restricted Subsidiary of any assets (including
by way of a sale-and-leaseback) other than (a) in the ordinary course of
business, (b) the sale, lease, conveyance or other disposition of all or
substantially all of the assets of the Company, which shall not be an "Asset



                                       2
<PAGE>   7

Sale" but instead shall be governed by the provisions of Section 801 of the Base
Indenture and Article V and Section 609 of this Supplemental Indenture and (c)
any "fee in lieu of" or other disposition of assets to any governmental
authority or agency that continue in use by the Company or any Restricted
Subsidiary, so long as the Company or any Restricted Subsidiary may obtain title
to such assets at any time upon reasonable notice by paying a nominal fee, or
(2) the issuance or sale of Capital Stock of any Restricted Subsidiary, in the
case of each of clauses (1) and (2), whether in a single transaction or a series
of related transactions, to any Person (other than the Company or a Restricted
Subsidiary) for Net Proceeds in excess of $5.0 million.

               "Attributable Value," when used with respect to any sale and
leaseback transaction means, as of the time of determination, the total
obligation (discounted to present value at the interest rate assumed in making
calculations in accordance with FAS 13) of the lessee for rental payments (other
than amounts required to be paid on account of property taxes as well as
maintenance, repairs, insurance, water rates and other items which do not
constitute payments for property rights) during the remaining portion of the
base term of the lease included in such sale and leaseback transaction.

               "Average Quoted Price" has the meaning specified in Section 501
of this Supplemental Indenture.

               "Bank Indebtedness" means any and all Indebtedness or other
amounts, whether outstanding on March 4, 1998 or thereafter incurred, payable
under or in respect of the Credit Facility or any refinancing in respect
thereof, and any Refinancing Indebtedness in respect thereof, including in each
case (without limitation) principal, premium (if any), interest (including
interest accruing on or after the filing of any petition in bankruptcy or for
reorganization relating to the Company or any Restricted Subsidiary whether or
not a claim for post-filing interest is allowed in such proceedings), fees,
charges, expenses, reimbursement obligations, Guarantees, other monetary
obligations of any nature and all other amounts payable under or in respect of
any of the foregoing (and, without limitation, whether incurred in accordance
with any clause of the definition of "Permitted Indebtedness" or the first
sentence of Section 605 of this Supplemental Indenture or otherwise).

               "Business Day" means each Monday, Tuesday, Wednesday, Thursday
and Friday which is not a day on which banking institutions in New York, New
York are authorized or obligated by law or executive order to close.

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

               "Capital Stock" of any Person means (1) in the case of a
corporation, corporate stock; (2) in the case of an association, limited
liability company or business entity, any and all Equity Interests; (3) in the
case of a partnership, partnership interests (whether general or limited); and
(4) any other interest or participation that confers on a Person the right to
receive a share of the profits and losses of, or distributions of assets of, the
issuing Person, including any Preferred Stock.



                                       3
<PAGE>   8

               "Cash Equivalents" means (1) marketable direct obligations issued
by, or unconditionally guaranteed by, the United States Government or issued by
any instrumentality or agency thereof and backed by the full faith and credit of
the United States, in each case maturing within one year from the date of
acquisition thereof; (2) marketable direct obligations issued by any state of
the United States of America or any political subdivision of any such state or
any public instrumentality or agency thereof maturing within one year from the
date of acquisition thereof and, at the time of acquisition, having one of the
two highest ratings obtainable from either Standard & Poor's Ratings Services or
Moody's Investors Service, Inc.; (3) commercial paper maturing no more than one
year from the date of creation thereof and, at the time of acquisition, having a
rating of at least A-1 from Standard & Poor's Rating Group or at least P-1 from
Moody's Investors Service, Inc.; (4) certificates of deposit, time deposits or
bankers' acceptances (or, with respect to foreign banks, similar instruments)
maturing within one year from the date of acquisition thereof issued by (a) any
lender under the Credit Agreement or (b) a commercial banking institution that
is a member of the Federal Reserve System or a commercial banking institution
organized and located in a country recognized by the United States of America,
in each case, having combined capital and surplus and undivided profits in
excess of $500,000,000 (or the foreign currency equivalent thereof); (5)
repurchase obligations with a term of not more than seven days for underlying
securities of the types described in clause (1) above entered into with any bank
meeting the qualifications specified in clause (4) above; (6) investments in
money market funds which invest substantially all their assets in securities of
the types described in clauses (1) through (5) above; and (7) other short-term
investments utilized by Foreign Subsidiaries in accordance with normal
investment practices for cash management not exceeding $50 million in aggregate
principal amount outstanding at any time.

               "Change of Control" means the occurrence of any of the following
(1) the sale, lease, transfer, conveyance or other disposition (other than by
way of merger or consolidation), in one or a series of related transactions, of
all or substantially all of the assets of the Company and its Subsidiaries taken
as a whole to any "person" (as such term is used in Section 13(d)(3) of the
Exchange Act); (2) the adoption of a plan relating to the liquidation or
dissolution of the Company; or (3) the consummation of any transaction
(including, without limitation, any merger or consolidation) the result of which
is that any "person" (as defined above), becomes the "beneficial owner" (as such
term is defined in Rule 13d-3 and Rule 13d-5 under the Exchange Act), directly
or indirectly, of more than 35% of the Voting Stock of the Company.

               "Closing Date" means the date of this Supplemental Indenture.

               "Code" means the Internal Revenue Code of 1986, as amended.

               "Commodity Price Protection Agreement" means any forward
contract, commodity swap, commodity option or other similar financial agreement
or arrangement relating to, or the value which is dependent upon, fluctuations
in commodity prices, but shall not include contracts for the purchase of raw
materials by the Company or any Restricted Subsidiary for its own use at fixed
prices in the ordinary course of business.

               "Common Stock" means the shares of Common Stock, par value $0.10
per share, of the Company as it exists on the date of this Supplemental
Indenture or any other shares of Capital Stock of the Company into which the
Common Stock shall be reclassified or changed.



                                       4
<PAGE>   9

               "Company" has the meaning specified in the recitals of this
Supplemental Indenture.

               "Company's Notice" has the meaning specified in Section 310 of
this Supplemental Indenture.

               "Company's Notice Date" has the meaning specified in Section 310
of this Supplemental Indenture.

               "Consolidated Cash Flow" means, with respect to any period, the
Consolidated Net Income for such period, plus without duplication (1)
Consolidated Interest Expense for such period; plus (2) provision for taxes
based on income, profits or capital, to the extent such provision for taxes was
included in computing such Consolidated Net Income; plus (3) depreciation,
amortization (including, without limitation, amortization of goodwill and other
intangibles) and all other non-cash charges (excluding any non-cash charge which
requires an accrual or reserve for cash charges for any future period), to the
extent such depreciation, amortization and other non-cash charges were deducted
in computing such Consolidated Net Income.

               "Consolidated Coverage Ratio" means, with respect to any date of
determination, the ratio of (1) the aggregate amount of Consolidated Cash Flow
for the period of the most recent four consecutive fiscal quarters ended prior
to such date for which consolidated financial statements of the Company are
available, to (2) Consolidated Interest Expense for such four fiscal quarters,
provided that:

               (1) if since the beginning of such period the Company or any
Restricted Subsidiary has incurred any Indebtedness that remains outstanding on
such date of determination, or if the transaction giving rise to the need to
calculate the Consolidated Coverage Ratio involves an incurrence of Indebtedness
(including without limitation any Acquired Debt), Consolidated Cash Flow and
Consolidated Interest Expense for such period shall be calculated after giving
effect on a pro forma basis to such Indebtedness and the application of the
proceeds thereof (and, in the case of any Acquired Debt, the related
acquisition) as if such Indebtedness had been incurred (and any such acquisition
had occurred) on the first day of such period;

               (2) if since the beginning of such period the Company or any
Restricted Subsidiary have repaid, repurchased, defeased, retired or otherwise
discharged (a "Discharge") any Indebtedness that is no longer outstanding on
such date of determination, or if the transaction giving rise to the need to
calculate the Consolidated Coverage Ratio involves a Discharge of Indebtedness,
Consolidated Cash Flow and Consolidated Interest Expense for such period shall
be calculated after giving effect to such Discharge of such Indebtedness,
including the proceeds of any such new Indebtedness, as if such Discharge had
occurred on the first day of such period;

               (3) if since the beginning of such period the Company or any
Restricted Subsidiary shall have disposed of any company, any business, any
group of assets constituting an operating unit, or any other assets out of the
ordinary course of business (a "Sale"), (a) Consolidated Cash Flow for such
period shall be reduced by an amount equal to the Consolidated Cash Flow (if
positive) directly attributable to the assets that are the subject of such



                                       5
<PAGE>   10

Sale for such period or increased by an amount equal to the Consolidated Cash
Flow (if negative) directly attributable thereto for such period and (b)
Consolidated Interest Expense for such period shall be reduced by an amount
equal to the Consolidated Interest Expense directly attributable to any of the
Indebtedness of the Company or that of any Restricted Subsidiary discharged with
respect to the Company and its continuing Restricted Subsidiaries in connection
with such Sale for such period (and, if the Capital Stock of any Restricted
Subsidiary is sold, transferred or otherwise disposed of, the Consolidated
Interest Expense for such period directly attributable to the Indebtedness of
such Restricted Subsidiary to the extent the Company and its continuing
Restricted Subsidiaries are no longer liable for such Indebtedness after such
sale, transfer or disposition);

               (4) if since the beginning of such period the Company or any
Restricted Subsidiary shall have acquired (by merger or otherwise, and whether
accounted for as a purchase, a pooling of interests or otherwise) any company,
any business, any group of assets constituting an operating unit, or any other
assets out of the ordinary course of business (a "Purchase"), Consolidated Cash
Flow and Consolidated Interest Expense for such period shall be calculated after
giving pro forma effect thereto (including the incurrence of any related
Indebtedness) as if such Purchase had occurred on the first day of such period;
and

               (5) if since the beginning of such period any Person became a
Restricted Subsidiary or was merged or consolidated with or into the Company or
any Restricted Subsidiary, in each case in a Purchase, and since the beginning
of such period such Person shall have Discharged any Indebtedness or made any
Sale or Purchase that would have required an adjustment pursuant to clause (2),
(3) or (4) above if made by the Company or a Restricted Subsidiary during such
period, Consolidated Cash Flow and Consolidated Interest Expense for such period
shall be calculated after giving pro forma effect thereto as if such Discharge,
Sale or Purchase occurred on the first day of such period.

               If any Indebtedness bears a floating rate of interest and is
being given pro forma effect, the interest expense on such Indebtedness shall be
calculated as if the rate in effect on the date of determination had been the
applicable rate for the entire period (taking into account any Interest Rate
Agreement applicable to such Indebtedness if such Interest Rate Agreement has a
remaining term as at the date of determination in excess of 12 months). If any
Indebtedness bears, at the option of the Company or a Restricted Subsidiary, a
fixed or floating rate of interest and is being given pro forma effect, the
interest expense on such Indebtedness shall be computed by applying, at the
option of the Company, either a fixed or floating rate. If any Indebtedness that
is being given pro forma effect was incurred under a revolving credit facility,
the interest expense on such Indebtedness shall be computed based upon the
average daily balance of such Indebtedness during the applicable period (being
the relevant four-quarter period or, if shorter, the portion thereof beginning
on the date such facility was first drawn upon).

               "Consolidated Interest Expense" means, with respect to any
period, the sum (without duplication) of (1) the interest expense of the Company
and its Restricted Subsidiaries for such period; plus (2) all cash dividends
paid during such period by the Company and its Restricted Subsidiaries with
respect to any Disqualified Stock (other than to the Company or a Restricted
Subsidiary); and minus (3) to the extent otherwise included in Consolidated
Interest



                                       6
<PAGE>   11

Expense, amortization or write-off of financing costs, in each case under
clauses (1) through (3) as determined on a consolidated basis in accordance with
GAAP consistently applied.

               "Consolidated Net Income" means, with respect to any period, the
net income (or loss) of the Company and its Restricted Subsidiaries for such
period, determined on a consolidated basis in accordance with GAAP consistently
applied, adjusted by excluding, to the extent included in calculating such net
income (or loss), without duplication (1) any extraordinary gain or loss as
recorded on the statement of operations in accordance with GAAP; (2) the portion
of net income (or loss) of the Company and its Restricted Subsidiaries allocable
to the Company's equity in the net income (or loss) of any unconsolidated Person
or Unrestricted Subsidiary, except (in the case of such net income) to the
extent of the amount of dividends or distributions actually paid or made to the
Company or any of its Restricted Subsidiaries by such other Person during such
period; (3) net income (or loss) of any Person combined with the Company or any
of its Restricted Subsidiaries on a "pooling of interests" basis attributable to
any period prior to the date of combination; (4) any gain or loss realized upon
any Asset Sale (other than sales of leases of customer-leased equipment) and any
gain or loss realized upon the sale or other disposition of any Capital Stock of
any Person; (5) the net income of any Restricted Subsidiary if the declaration
of dividends or similar distributions by that Restricted Subsidiary of that net
income to the Company is at the time restricted, directly or indirectly, by
operation of the terms of its charter or any agreement, instrument, judgment,
decree, order, statute, rule or governmental regulation (other than pursuant to
any statute, rule or governmental regulation that permits such dividends or
similar distributions payments after the passage of time, not to exceed 120
days, or after the filing or providing of notice with respect to such dividends
or similar distributions) applicable to that Restricted Subsidiary or its
stockholders (other than pursuant to the Notes or the Indenture), except to the
extent that any dividend or distribution was or could have been made by the
Restricted Subsidiary to the Company or another Restricted Subsidiary during
such period in compliance with such restrictions; (6) non-cash, nonrecurring
charges (excluding any non-cash charge which requires an accrual or reserve for
cash charges for any future period); (7) any nonrecurring charges related to the
Acquisition or any acquisition by the Company or any Restricted Subsidiary after
March 4, 1998; and (8) all deferred financing costs written off and premium paid
in connection to any early extinguishment of Indebtedness.

               "Consolidated Net Tangible Assets" means the aggregate amount of
assets (less applicable reserves and other properly deductible items) after
deducting therefrom (1) all current liabilities (excluding any indebtedness for
money borrowed having a maturity of less than 12 months from the date of the
most recent consolidated balance sheet of the Company but which by its terms is
renewable or extendable beyond 12 months from such date at the option of the
borrower); and (2) all goodwill, trade names, patents, unamortized debt discount
and expense and any other like intangibles, all as set forth on the most recent
consolidated balance sheet of the Company and computed in accordance with GAAP.

               "Conversion Agent" has the meaning specified in Section 302 of
this Supplemental Indenture.

               "Conversion Date" has the meaning specified in Section 502 of
this Supplemental Indenture.



                                       7
<PAGE>   12

               "Conversion Rate" has the meaning specified in Section 501 of
this Supplemental Indenture.

               "Credit Agreement" means the credit agreement dated as of October
31, 1997, among the Company, the banks and other financial institutions party
thereto from time to time, the initial issuing bank named therein, Citicorp USA,
Inc., as agent and Citicorp Securities, Inc., as arranger, as such agreement may
be amended, supplemented, waived or otherwise modified from time to time, or
refunded, refinanced, restructured, replaced, renewed, repaid, increased or
extended from time to time (whether in whole or in part, whether with the
original agents and lenders or other agents and lenders or otherwise, and
whether provided under the original Credit Agreement or otherwise).

               "Credit Facility" means the collective reference to the Credit
Agreement, any notes and letters of credit issued pursuant thereto and any
guarantees, security agreements, pledges, mortgages, letter of credit
applications and other collateral documents, and other instruments and
documents, executed and delivered pursuant to or in connection with any of the
foregoing, in each case as the same may be amended, supplemented, waived or
otherwise modified from time to time, or refunded, refinanced, restructured,
replaced, renewed, repaid, increased or extended from time to time (whether in
whole or in part, whether with the original agents and lenders or other agents
and lenders or otherwise, and whether provided under the original Credit
Agreement or otherwise).

               "Currency Hedging Arrangements" means one or more of the
following agreements which shall be entered into by one or more financial
institutions: foreign exchange contracts, currency swap agreements or other
similar agreements or arrangements designed to protect against the fluctuations
in currency values.

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

               "Defaulted Interest" has the meaning specified in Section 404 of
this Supplemental Indenture.

               "Disqualified Stock" means (1) any Preferred Stock of any
Restricted Subsidiary; and (2) any Capital Stock that, by its terms (or by the
terms of any security into which such Capital Stock is convertible or for which
such Capital Stock is exchangeable), or upon the happening of any event, matures
or is mandatorily redeemable, pursuant to a sinking fund obligation or
otherwise, or is redeemable at the option of the holder thereof (other than upon
a change of control of the Company in circumstances where the holders of the
notes would have similar rights), in whole or in part on or prior to the stated
maturity of the notes.

               "Dollar" means a dollar or other equivalent unit in such coin or
currency of the United States as at the time shall be legal tender for the
payment of public and private debt.

               "Equipment Held for Resale" means instrument systems and related
accessories and components manufactured or assembled by the Company that are
owned and held for placement in facilities of the Company's customers.



                                       8
<PAGE>   13

               "Equity Interest" in any Person means any and all shares,
interests, rights to purchase, warrants, options, participations or other
equivalents of or interests in (however designated) corporate stock or other
equity participations, including limited liability company interests, in such
Person.

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

               "Ex-Dividend Time" has the meaning specified in Section 501 of
this Supplemental Indenture.

               "Fair Market Value" means, with respect to any asset or property,
the sale value that would be obtained in an arm's-length transaction between an
informed and willing seller under no compulsion to sell and an informed and
willing buyer under no compulsion to buy.

               "Foreign Subsidiary" means any Restricted Subsidiary of the
Company that (1) is not organized under the laws of the United States of America
or any state thereof or the District of Columbia; and (2) conducts its principal
operations outside the United States.

               "Fundamental Change" has the meaning specified in Section 311 of
this Supplemental Indenture.

               "Fundamental Change Notice" has the meaning specified in Section
311 of this Supplemental Indenture.

               "Fundamental Change Notice Date" has the meaning specified in
Section 311 of this Supplemental Indenture.

               "Fundamental Change Repurchase Date" has the meaning specified in
Section 311 of this Supplemental Indenture.

               "Fundamental Change Repurchase Notice" has the meaning specified
in Section 311 of this Supplemental Indenture.

               "Fundamental Change Repurchase Price" has the meaning specified
in Section 311 of this Supplemental Indenture.

               "GAAP" means generally accepted accounting principles in the
United States of America as in effect on March 4, 1998, including those 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
statement by such other entity as approved by a significant segment of the
United States accounting profession.

               "Guarantee" means any obligation, contingent or otherwise, of any
Person directly or indirectly guaranteeing any Indebtedness or other obligation
of any other Person, and any obligation, direct or indirect, contingent or
otherwise, of such Person (1) to purchase or pay (or advance or supply funds for
the purchase or payment of) such Indebtedness or other obligation of such Person
(whether arising by virtue of partnership arrangements, or by



                                       9
<PAGE>   14

agreement to keep well, to purchase assets, goods, securities or services, to
take-or-pay, or to maintain financial statement conditions or otherwise); or (2)
entered into for purposes of assuring in any other manner the obligee of such
Indebtedness or other obligation of the payment thereof or to protect such
obligee against loss in respect thereof (in whole or in part), provided,
however, that the term "Guarantee" shall not include endorsements for collection
or deposit in the ordinary course of business. The term "Guarantee" used as a
verb has a corresponding meaning.

               "Guarantors" means each of Coulter Corporation and Hybritech
Incorporated and any Restricted Subsidiary that has issued a Note Guarantee.

               "Indebtedness" means, with respect to any Person, without
duplication, and whether or not contingent (1) all indebtedness of such Person
for borrowed money or which is evidenced by a note, bond, debenture or similar
instrument; (2) all obligations of such Person to pay the deferred or unpaid
purchase price of property or services, which purchase price is due more than
one year after the date of placing such property in service or taking delivery
and title thereto or the completion of such service; (3) all Capital Lease
Obligations of such Person; (4) all obligations of such Person in respect of
letters of credit or bankers' acceptances issued or created for the account of
such Person; (5) to the extent not otherwise included in this definition, all
net obligations of such Person under all Interest Rate Agreement Obligations,
Currency Hedging Arrangements or Commodity Price Protection Agreements of such
Person; (6) all liabilities of others of the kind described in the preceding
clause (1), (2) or (3) secured by any Lien on any property owned by such Person
even if such Person has not assumed or otherwise become liable for the payment
thereof, to the extent of the value of the property subject to such Lien; (7)
all Disqualified Stock issued by such Person; and (8) to the extent not
otherwise included, any Guarantee by such Person of any other Person's
indebtedness or other obligations described in clauses (1) through (7) above.
"Indebtedness" of the Company and its Restricted Subsidiaries shall not include
(1) current trade payables incurred in the ordinary course of business and
payable in accordance with customary practices; and (2) non-interest bearing
installment obligations and accrued liabilities incurred in the ordinary course
of business which are not more than 90 days past due.

               "Indenture" means the Base Indenture as originally executed, as
supplemented by this Supplemental Indenture and as it may from time to time be
supplemented or amended by one or more indentures supplemental thereto entered
into pursuant to the applicable provisions thereof, including, for all purposes
of that instrument and any such supplemental indenture, the provisions of the
Trust Indenture Act that are deemed to be a part of and govern that instrument
and any such supplemental indenture, respectively.

               "Indenture Obligations" means the obligations of the Company and
any other obligor under this Supplemental Indenture or under the Notes, to pay
principal of, premium, if any, and interest on the Notes when due and payable,
whether at maturity, by acceleration, call for redemption or repurchase or
otherwise, and all other amounts due or to become due under or in connection
with this Supplemental Indenture, the Notes or the Note Guarantees and the
performance of all other obligations to the Trustee (including, but not limited
to, payment of all amounts due the Trustee under Section 607 of the Base
Indenture) and the Holders of the Notes under this Indenture, the Notes and the
Note Guarantees, according to the terms thereof.



                                       10
<PAGE>   15

               "Interest Rate Agreements" means one or more of the following
agreements which shall be entered into by one or more financial institutions:
interest rate protection agreements (including, without limitation, interest
rate swaps, caps, floors, collars and similar agreements) and/or other types of
interest rate hedging agreements from time to time.

               "Investment" in any Person means any direct or indirect advance,
loan or other extension of credit (including, without limitation, by way of
Guarantee or similar arrangement, but excluding advances, loans and other
extension of credit to customers, directors, officers and employees in the
ordinary course of business) to, capital contribution (by means of any transfer
of cash or other property to others or any payment for property or services for
the account or use of others) to, or any purchase or acquisition of Capital
Stock, bonds, notes, securities or other similar instruments issued by, such
Person and shall include the designation of a Restricted Subsidiary as an
Unrestricted Subsidiary. For purposes of the definition of "Unrestricted
Subsidiary" and Section 606 of this Supplemental Indenture, (1) "Investment"
shall include the portion (proportionate to the Company's equity interest in
such Subsidiary) of the Fair Market Value of the assets (net of liabilities) of
any Restricted Subsidiary at the time that such Restricted Subsidiary is
designated an Unrestricted Subsidiary and shall exclude the Fair Market Value of
the assets (net of liabilities) of any Unrestricted Subsidiary at the time that
such Unrestricted Subsidiary is designated a Restricted Subsidiary; and (2) any
property transferred to or from an Unrestricted Subsidiary shall be valued at
its Fair Market Value at the time of such transfer, in each case as determined
by the Board of Directors in good faith.

               "Investment Grade" means a rating in one of the four highest
categories (without regard to subcategories within such rating categories) by a
Rating Agency.

               "Investment Grade Rating Date" means the first date on which the
notes are rated Investment Grade by two Rating Agencies.

               "Issue Price" of any Note means, in connection with the original
issuance of such Note, the initial issue price at which the Note is sold as set
forth on the face of the Note.

               "Lien" means, with respect to any property or assets, any
mortgage or deed of trust, pledge, hypothecation, assignment, security interest,
lien, encumbrance, or other security arrangement of any kind or nature
whatsoever on or with respect to such property or assets (including any
conditional sale or other title retention agreement having substantially the
same economic effect as any of the foregoing).

               "Market Price" has the meaning specified in Section 310 of this
Supplemental Indenture.

               "Net Proceeds" from an Asset Sale means cash payments received
(including any cash payments received by way of deferred payment of principal
pursuant to a note or installment receivable or otherwise, but only as and when
received, but excluding any other consideration received in the form of
assumption by the acquiring Person of Indebtedness or other obligations relating
to the properties or assets that are the subject of such Asset Sale or received
in any other noncash form) therefrom, in each case net of (1) all legal, title
and recording tax expenses, commissions and other fees and expenses incurred,
and all federal, state,



                                       11
<PAGE>   16

provincial, foreign and local taxes required to be paid or accrued as a
liability under GAAP, as a consequence of such Asset Sale, (2) all payments made
on any Indebtedness that is secured by any assets subject to such Asset Sale, in
accordance with the terms of any Lien upon such assets, (3) all distributions
and other payments required to be made to minority interest holders in
Subsidiaries or joint ventures as a result of such Asset Sale, or to any other
Person (other than the Company or a Restricted Subsidiary) owning a beneficial
interest in the assets disposed of in such Asset Sale and (4) appropriate
amounts to be provided as a reserve, in accordance with GAAP, against any
liabilities associated with the assets disposed of in such Asset Sale and
retained by the Company or any Restricted Subsidiary after such Asset Sale.

               "Note Guarantee" means each guarantee of the Notes by the
Guarantors hereunder and any guarantee of the Notes that may from time to time
be executed and delivered pursuant to the terms of this Supplemental Indenture.

               "Notes" has the meaning specified in the recitals of this
Supplemental Indenture.

               "Officer" means the Chairman of the Board, the Chief Executive
Officer, the Chief Financial Officer, the President, any Vice President, the
Treasurer or the Secretary of the Company.

               "Option Exercise Date" has the meaning specified in Section 401
of this Supplemental Indenture.

               "Paying Agent" has the meaning specified in Section 302 of this
Supplemental Indenture.

               "Permitted Indebtedness" means:

               (1) Indebtedness incurred by the Company pursuant to the Credit
Facility in an aggregate principal amount not to exceed $1,100.0 million
outstanding at any time, minus the aggregate amount of all scheduled repayments
of principal, and all mandatory prepayments of principal with Net Proceeds from
Asset Sales, and plus (in the case of any refinancing thereof) the aggregate
amount of fees, underwriting discounts, premiums and other costs and expenses
incurred in connection with such refinancing; provided that, so long as no term
loan Indebtedness remains outstanding under the Credit Facility, the Company
shall be permitted to incur revolving credit Indebtedness thereunder in an
aggregate principal amount not to exceed $800 million outstanding at any time;

               (2) Indebtedness of Foreign Subsidiaries in an aggregate
principal amount outstanding at any time not exceeding, as to all such Foreign
Subsidiaries, the greater of (a) $75 million and (b) an amount equal to the sum
of (x) 80% of the combined book value of the net account receivables owned by
Foreign Subsidiaries that are shown on the consolidated balance sheet of the
Company as of the end of the most recently ended fiscal quarter for which
financial statements of the Company are available plus (y) 50% of the combined
book value of the inventory owned by Foreign Subsidiaries that is shown on such
balance sheet, all as calculated on a combined basis and in accordance with
GAAP;



                                       12
<PAGE>   17

               (3) Indebtedness represented by the Notes, any Note Guarantees in
respect thereof, and any Indebtedness arising by reason of any Lien granted to
secure any of the foregoing Indebtedness;

               (4) Indebtedness owed by any Restricted Subsidiary to the Company
or to another Restricted Subsidiary, or owed by the Company to any Restricted
Subsidiary; provided, however, that any such Indebtedness shall be at all times
held by a Person that is either the Company or a Restricted Subsidiary of the
Company; provided, further however, that upon either (a) the transfer or other
disposition of any such Indebtedness to a Person other than the Company or
another Restricted Subsidiary or (b) the sale, lease, transfer or other
disposition of shares of Capital Stock (including by consolidation or merger) of
any such Restricted Subsidiary to a Person other than the Company or another
Restricted Subsidiary, the incurrence of such Indebtedness shall be deemed to be
an incurrence that is not permitted by this clause (4);

               (5) Indebtedness of the Company or any Restricted Subsidiary in
the form of Purchase Money Obligations or Capital Lease Obligations, in an
aggregate amount not in excess of $30 million outstanding at any time;

               (6) Indebtedness of the Company or any Restricted Subsidiary
arising in the ordinary course of business (a) pursuant to Interest Rate
Agreements designed to protect the Company or any Subsidiary against
fluctuations in interest rates in respect of Indebtedness of the Company or any
Subsidiary as long as such obligations do not exceed the aggregate principal
amount of such Indebtedness then outstanding, (b) under any Currency Hedging
Arrangements, which if related to Indebtedness do not increase the amount of
such Indebtedness other than as a result of foreign exchange fluctuations, or
(c) under any Commodity Price Protection Agreements, which if related to
Indebtedness do not increase the amount of such Indebtedness other than as a
result of foreign exchange fluctuations;

               (7) Indebtedness of the Company or any Restricted Subsidiary
arising from the honoring of a check, draft or similar instrument of such Person
drawn against insufficient funds, provided that such Indebtedness is
extinguished within five Business Days of its incurrence;

               (8) Indebtedness of the Company or any Restricted Subsidiary
consisting of Guarantees, indemnities, or obligations in respect of purchase
price adjustments, in connection with the acquisition or disposition of assets;

               (9) Indebtedness of the Company or any Restricted Subsidiary in
respect of (a) judgment, performance, surety and other bonds provided by such
Person with respect to obligations of such Person in the ordinary course of
business, (b) letters of credit securing obligations incurred in the ordinary
course of business or (c) other letters of credit in an amount not to exceed $5
million in the aggregate outstanding at any time;

               (10) Indebtedness of the Company or any Restricted Subsidiary
consisting of Guarantees in respect of loans or advances made to officers or
employees of the Company or any Restricted Subsidiary, or Guarantees otherwise
made on their behalf (a) in respect of travel, entertainment and moving related
expenses incurred in the ordinary course of business, or (b) in



                                       13
<PAGE>   18

the ordinary course of business not exceeding $2,500,000 in the aggregate
outstanding at any time;

               (11) Any Refinancing Indebtedness incurred in respect of any
Indebtedness described in clauses (1), (2), (3), (11), (12) or (13) of this
definition of "Permitted Indebtedness," any Capital Lease Obligations described
in clause (5) of this definition of "Permitted Indebtedness" or any Indebtedness
permitted to be incurred pursuant to the first sentence of the covenant
described in the first sentence of Section 605 of this Supplemental Indenture;

               (12) Indebtedness of the Company or any Restricted Subsidiary
that is outstanding on the date of original issuance of the Notes;

               (13) Acquired Debt of any Restricted Subsidiary, provided that at
the time of the incurrence thereof and after giving effect thereto on a pro
forma basis, (a) no Default or Event of Default will have occurred and be
continuing or would result therefrom and (b) the Company could incur at least
$1.00 of additional Indebtedness pursuant to the first sentence of the covenant
described in Section 605 of this Supplemental Indenture;

               (14) Indebtedness of any Restricted Subsidiary in an aggregate
principal amount not exceeding $30 million outstanding at any time, as to all
such Restricted Subsidiaries that incur Indebtedness pursuant to this clause
(14);

               (15) Guarantees by the Company of any Indebtedness of any
Restricted Subsidiary incurred by such Subsidiary in compliance with the
covenant described under Section 605 of this Supplemental Indenture, provided
that if such Indebtedness is subordinated in right of payment to any other
Indebtedness, such Guarantee shall be subordinated in right of payment to the
notes at least to the same extent as such Indebtedness is so subordinated to
such other Indebtedness;

               (16) any Guarantee of Bank Indebtedness of the Company incurred
pursuant to clause (1), (11) or (17) of this definition of "Permitted
Indebtedness" or the first sentence of the covenant described under Section 605
of this Supplemental Indenture, provided that if such Indebtedness is
subordinated in right of payment to any other Indebtedness, such Guarantee shall
be subordinated in right of payment to the notes at least to the same extent as
such Indebtedness is so subordinated to such other Indebtedness; and

               (17) Indebtedness of the Company in addition to that described in
clauses (1), (3) through (12) and (15) above, and any renewals, extensions,
substitutions, refinancings or replacements of such Indebtedness, so long as the
aggregate principal amount of all such Indebtedness incurred pursuant to this
clause (17) does not exceed $100 million outstanding at any time.

               For purposes of determining compliance with any such
Dollar-denominated restriction on the incurrence of Indebtedness denominated in
a foreign currency, the Dollar-equivalent principal amount of such Indebtedness
incurred pursuant thereto shall be calculated based on the relevant currency
exchange rate in effect on the date that such Indebtedness was incurred, in the
case of term debt, or first committed, in the case of revolving credit debt,
provided that (x) the Dollar-equivalent principal amount of any such
Indebtedness outstanding



                                       14
<PAGE>   19

on March 4, 1998 shall be calculated based on the relevant currency exchange
rate in effect on March 4, 1998; (y) if such Indebtedness is incurred to
refinance other Indebtedness denominated in a foreign currency, and such
refinancing would cause the applicable Dollar-denominated restriction to be
exceeded if calculated at the relevant currency exchange rate in effect on the
date of such refinancing, such Dollar-denominated restriction shall be deemed
not to have been exceeded so long as the principal amount of such refinancing
Indebtedness does not exceed the principal amount of such Indebtedness being
refinanced; and (z) the Dollar-equivalent principal amount of Indebtedness
denominated in a foreign currency and incurred pursuant to the Credit Facility
shall be calculated based on the relevant currency exchange rate in effect on,
at the option of the Company, (1) March 4, 1998, (2) any date on which any of
the respective commitments under the Credit Facility shall be reallocated
between or among facilities or subfacilities thereunder, or on which such rate
is otherwise calculated for any purpose thereunder, or (3) the date of such
incurrence. The principal amount of any Indebtedness incurred to refinance other
Indebtedness, if incurred in a different currency from the Indebtedness being
refinanced, shall be calculated based on the currency exchange rate applicable
to the currencies in which such respective Indebtedness is denominated that is
in effect on the date of such refinancing.

               For purposes of determining compliance with, and the outstanding
principal amount of any particular Indebtedness incurred pursuant to and in
compliance with, the covenant described under Section 605 of this Supplemental
Indenture, (1) any other obligation of the obligor on such Indebtedness (or of
any other Person that could have incurred such Indebtedness as the obligor
thereon in compliance with such covenant) arising under any Guarantee, Lien or
letter of credit supporting such Indebtedness shall be disregarded to the extent
that such Guarantee, Lien or letter of credit secures the principal amount of
such Indebtedness; (2) in the event that Indebtedness is entitled to be incurred
pursuant to the first paragraph of such covenant or meets the criteria of more
than one of the types of Indebtedness described in the definition of "Permitted
Indebtedness," the Company, in its sole discretion, shall classify such item of
Indebtedness and only be required to include the amount and type of such
Indebtedness in one of such clauses; and (3) the amount of Indebtedness issued
at a price that is less than the principal amount thereof shall be equal to the
amount of the liability in respect thereof determined in accordance with GAAP.

               Indebtedness of any Person that is not a Restricted Subsidiary,
which Indebtedness is outstanding at the time such Person becomes a Restricted
Subsidiary or is merged with or into or consolidated with the Company or a
Restricted Subsidiary, shall be deemed to have been incurred at the time such
Person becomes a Restricted Subsidiary or is merged with or into or consolidated
with the Company or a Restricted Subsidiary, and Indebtedness which is assumed
at the time of the acquisition of any asset shall be deemed to have been
incurred at the time of such acquisition. Accrual of interest, the accretion of
accreted value of principal, and the payment of interest in the form of
additional Indebtedness having the same terms as the original Indebtedness on
which such payment is made (which payment is made pursuant to the terms of such
original Indebtedness as initially issued), will not be deemed an incurrence of
Indebtedness for purposes of the covenant described under Section 605 of this
Supplemental Indenture.



                                       15
<PAGE>   20

               "Permitted Investments" means (1) any Investment in the Company
or any Restricted Subsidiary; (2) any Investment in Cash Equivalents; (3) any
Investment in a Person if, as a result of such Investment, (a) such Person
becomes a Restricted Subsidiary, or (b) such Person either (1) is merged,
consolidated or amalgamated with or into the Company or one of its Restricted
Subsidiaries and the Company or such Restricted Subsidiary are the surviving
Person, or (2) transfers or conveys substantially all of its assets to, or is
liquidated into, the Company or one of its Restricted Subsidiaries; (4)
Investments in accounts and notes receivable acquired in the ordinary course of
business; (5) any securities or other Investments received in connection with
any sale or other disposition of property or assets (including Equity
Interests); (6) obligations under any Interest Rate Agreement, Currency Hedging
Arrangement or Commodity Price Protection Agreement permitted pursuant to
Section 605 of this Supplemental Indenture; (7) securities or other Investments
received in settlement of debts created in the ordinary course of business and
owing to the Company or any Restricted Subsidiary, or as a result of
foreclosure, perfection or enforcement of any Lien, or in satisfaction of
judgments, including in connection with any bankruptcy proceeding or other
reorganization of another Person; (8) Investments in existence or made pursuant
to legally binding written commitments in existence on the Issue Date; (9)
pledges or deposits with respect to leases or utilities, provided to third
parties in the ordinary course of business; (10) bonds secured by assets leased
to and operated by the Company or any Restricted Subsidiary that were issued in
connection with the financing of such assets so long as the Company or any
Restricted Subsidiary may obtain title to such assets at any time by paying a
nominal fee, canceling such bonds and terminating the transaction; (11)
Investments in a joint venture or similar entity that is not a Restricted
Subsidiary, made in the ordinary course of business; (12) Investments in
customers or suppliers, not to exceed $50 million in the aggregate outstanding
at any time; and (13) Investments in an amount not exceeding $200 million in the
aggregate outstanding at any time.

               "Person" means any individual, corporation, partnership, joint
venture, association, joint-stock company, limited liability company, trust,
unincorporated organization or government or any agency or political subdivision
thereof.

               "Preferred Stock" as applied to the Capital Stock of any Person,
means Capital Stock of any class or classes (however designated) which is
preferred as to the payment of dividends or distributions, or as to the
distribution of assets upon any voluntary or involuntary liquidation or
dissolution of such Person, over Capital Stock of any other class of such
Person.

               "Principal Amount at Maturity" of a Note means the Principal
Amount at Maturity as set forth on the face of the Note.

               "Principal Property" means any real property of the Company or
any of its Subsidiaries, and any equipment located at or comprising a part of
any such property, having a net book value, as of the date of determination, in
excess of the greater of $50 million and 10% of Consolidated Net Tangible Assets
of the Company; provided, however, that Principal Property shall not include
Equipment Held for Resale.

               "Purchase Date" has the meaning specified in Section 310 of this
Supplemental Indenture.



                                       16
<PAGE>   21

               "Purchase Money Obligation" means any Indebtedness secured by a
Lien on assets related to the business of the Company or the Restricted
Subsidiaries, and any additions and accessions thereto, which are purchased or
constructed by the Company or any Restricted Subsidiary at any time after March
4, 1998; provided that (1) any security agreement or conditional sales or other
title retention contract pursuant to which the Lien on such assets is created
(collectively a "Security Agreement") shall be entered into within 180 days
after the purchase or substantial completion of the construction of such assets
and shall at all times be confined solely to the assets so purchased or
acquired, any additions and accessions thereto and any proceeds therefrom; (2)
at no time shall the aggregate principal amount of the outstanding Indebtedness
secured thereby be increased, except in connection with the purchase of
additions and accessions thereto and except in respect of fees and other
obligations in respect of such Indebtedness; and (3) (a) the aggregate
outstanding principal amount of Indebtedness secured thereby (determined on a
per asset basis in the case of any additions and accessions) shall not at the
time such Security Agreement is entered into exceed 100% of the purchase price
to the Company or any Restricted Subsidiary of the assets subject thereto or (b)
the Indebtedness secured thereby shall be with recourse solely to the assets so
purchased or acquired, any additions and accessions thereto and any proceeds
therefrom.

               "Purchase Notice" has the meaning specified in Section 310 of
this Supplemental Indenture.

               "Purchase Price" has the meaning specified in Section 310 of this
Supplemental Indenture.

               "Rating Agency" means each of Standard & Poor's Ratings Services,
Fitch IBCA Duff & Phelps Credit Rating Co. and Moody's Investors Service, Inc.
(or, in any case, if such Person ceases to rate the notes for reasons outside
the control of the Company, any other "nationally recognized statistical rating
organization" (within the meaning of Rule 15c3-1(c)(2)(6)(F) under the Exchange
Act) selected by the Company as a replacement Rating Agency).

               "Refinancing Indebtedness" means any Indebtedness incurred in
connection with or given in exchange for the renewal, extension, substitution,
refunding, defeasance, refinancing, repayment or replacement (a "refinancing")
of any Indebtedness described in clauses (1), (2), (3), (11), (12) or (13) of
the definition of "Permitted Indebtedness," any Capital Lease Obligations
described in clause (5) of the definition of "Permitted Indebtedness" or any
Indebtedness permitted to be incurred pursuant to the first sentence of the
covenant described in Section 605 of this Supplemental Indenture; provided,
however, that (1) the principal amount of such Refinancing Indebtedness shall
not exceed the principal amount (or accrued amount, if less) of the Indebtedness
so renewed, extended, substituted, refunded, defeased, refinanced or replaced
("refinanced"), plus the reasonable fees, underwriting discounts, premiums and
other costs and expenses incurred in connection therewith, (2) such Refinancing
Indebtedness shall have a Weighted Average Life to Maturity equal to or greater
than the Weighted Average Life to Maturity of the Indebtedness being refinanced;
(3) if the Indebtedness being refinanced is subordinated in right of payment to
the notes, such Refinancing Indebtedness shall be at least as subordinated in
right of payment to the notes as the Indebtedness being refinanced; and (4) the
obligor on such Refinancing Indebtedness shall be the obligor on the
Indebtedness being



                                       17
<PAGE>   22

refinanced, the Company, or (in the case of Indebtedness of a Foreign Subsidiary
that is being refinanced) any Foreign Subsidiary; it being understood that any
Indebtedness incurred pursuant to clauses (1), (2) or (5) of the definition of
"Permitted Indebtedness" that is so refinanced shall be deemed to remain
outstanding for the purpose of determining compliance with any limitations or
restrictions set forth in such clauses.

               "Registrar" has the meaning specified in Section 302 of this
Supplemental Indenture.

               "Restated Principal Amount" has the meaning specified in Section
401 of this Supplemental Indenture.

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

               "Restricted Payment" means: (1) any dividend or other
distribution declared or paid on any Capital Stock of the Company or any of its
Restricted Subsidiaries (other than dividends or distributions payable solely in
Capital Stock other than Disqualified Stock of the Company or such Restricted
Subsidiary) or dividends or distributions payable to the Company or any
Restricted Subsidiary (and, if the Restricted Subsidiary making such dividend or
distributions has any stockholder other than the Company or another Restricted
Subsidiary, to such stockholder on no more than a pro rata basis, measured by
value); (2) any payment to purchase, redeem or otherwise acquire or retire for
value any of the Capital Stock of the Company or any Restricted Subsidiary
(other than any Capital Stock owned by the Company or any Restricted Subsidiary,
or from all holders of such Capital Stock of a Restricted Subsidiary on a pro
rata basis); (3) any payment to purchase, redeem, defease or otherwise acquire
or retire for value any Indebtedness that is subordinated in right of payment to
the notes (other than a purchase, redemption, defeasance or other acquisition or
retirement for value in anticipation of satisfying a sinking fund obligation,
principal installment or final maturity, in each case due within one year of the
date of such acquisition or retirement); or (4) any Restricted Investment.

               "Restricted Payment Amount" means the sum of:

               (1) an amount equal to 50% of the Company's aggregate cumulative
Consolidated Net Income accrued on a cumulative basis from March 4, 1998 (or, if
such aggregate cumulative Consolidated Net Income for such period shall be a
deficit, minus 100% of such deficit); plus

               (2) the aggregate amount of all net cash proceeds received by the
Company since March 4, 1998 (a) as capital contributions to the Company in the
form of common equity after March 4, 1998, (b) from the issuance and sale (other
than to a Restricted Subsidiary) of the Company's Capital Stock (other than
Disqualified Stock), (c) from the issuance to a Person who is not a Subsidiary
of the Company of any options, warrants or other rights to acquire the Company's
Capital Stock (in each case, exclusive of any Disqualified Stock or any options,
warrants or other rights that are redeemable at the option of the holder, or are
required to be redeemed, prior to the Stated Maturity of the notes) and (d) from
the issuance and sale by the Company or any Restricted Subsidiary after March 4,
1998 of Disqualified Stock or debt securities that have been converted into or
exchanged for the Company's Capital Stock (other



                                       18
<PAGE>   23

than Disqualified Stock), plus the amount of cash received by the Company or any
Restricted Subsidiary upon such conversion or exchange, in each case to the
extent that such proceeds are not used to redeem, repurchase, retire or
otherwise acquire Capital Stock or any Indebtedness of the Company or any
Restricted Subsidiary, pursuant to clause (2) or (3) of the second paragraph of
the covenant described under Section 606 of this Supplemental Indenture, plus

               (3) the amount of the net reduction in Investments by the Company
in Unrestricted Subsidiaries resulting from (x) the payment of cash dividends or
the repayment in cash of the principal of loans or the cash return on any
Investment, in each case to the extent received by the Company or any Restricted
Subsidiary from Unrestricted Subsidiaries, (y) the release or extinguishment of
any Guarantee of Indebtedness of any Unrestricted Subsidiary, and (z) the
redesignation of Unrestricted Subsidiaries as Restricted Subsidiaries of the
Company (valued as provided in the definition of "Investment"), such aggregate
amount of the net reduction in Investments not to exceed in the case of any
Unrestricted Subsidiaries the amount of Restricted Investments previously made
by the Company or any Restricted Subsidiary in such Unrestricted Subsidiary,
which amount was included in the calculation of the amount of Restricted
Payments, plus

               (4) to the extent that any Restricted Investment that was made
after March 4, 1998 is sold for cash or otherwise liquidated or repaid for cash,
the amount of cash proceeds received with respect to such Restricted Investment,
net of taxes and the cost of disposition, not to exceed the amount of Restricted
Investments made after March 4, 1998.

               "Restricted Subsidiary" means any Subsidiary of the Company which
owns or leases a Principal Property; provided that, prior to an Investment Grade
Rating Date, "Restricted Subsidiary" means any Subsidiary of the Company (other
than an Unrestricted Subsidiary) for all purposes other than as used in the
Section 603 and 604 of this Supplemental Indenture.

               "Rights" has the meaning specified in Section 519 of this
Supplemental Indenture.

               "Rights Agreement" has the meaning specified in Section 519 of
this Supplemental Indenture.

               "Sale Price" has the meaning specified in Section 310 of this
Supplemental Indenture.

               "Securities" has the meaning specified in the recitals of this
Supplemental Indenture.

               "Securities Custodian" means the custodian with respect to a
Global Note (as appointed by the Depositary) or any successor thereto, who shall
initially be the Trustee.

               "Stated Maturity" means, when used with respect to any security,
the date specified in such security as the fixed date on which the payment of
principal of such security is due and payable, including pursuant to any
mandatory redemption provision (but excluding any provision providing for the
purchase of such security at the option of the holder thereof upon the happening
of any contingency beyond the control of the issuer unless such contingency has
occurred).



                                       19
<PAGE>   24

               "Stock Transfer Agent" means the transfer agent for delivery of
Common Stock hereunder, or any successor thereto, who shall initially be the
Trustee.

               "Subsidiary" of a Person means a Person more than 50% of the
outstanding voting stock or other Equity Interests of which is owned, directly
or indirectly, by the Company or by one or more other Subsidiaries, or by the
Company and one or more other Subsidiaries. For the purposes of this definition,
"voting" stock or other Equity Interests means stock or other Equity Interests
which ordinarily has voting power for the election of directors, trustees or
similar managers, whether at all times or only so long as no senior class of
stock or other Equity Interests has such voting power by reason of any
contingency.

               "Supplemental Indenture" has the meaning specified in the
recitals of this Supplemental Indenture.

               "Tax Event" means that the Company shall have received an opinion
from independent tax counsel experienced in such matters to the effect that, on
or after June ___, 2001, as a result of (a) any amendment to, or change
(including any announced prospective change) in, the laws, rules or any
regulations thereunder of the United States or any political subdivision or
taxing authority thereof or therein or (b) any amendment to, or change in, an
interpretation or application of such laws or regulations by any legislative
body, court, governmental agency or regulatory authority, in each case which
amendment or change is enacted, promulgated, issued or announced or which
interpretation is issued or announced or which action is taken, on or after June
___, 2001, there is more than an insubstantial risk that interest (including
Original Issue Discount) payable on the Notes either (i) would not be deductible
on a current accrual basis or (ii) would not be deductible under any other
method, in either case in whole or in part, by the Company (by reason of
deferral, disallowance, or otherwise) for United States Federal income tax
purposes.

               "Tax Event Date" has the meaning specified in Section 401 of this
Supplemental Indenture.

               "Time of Determination" has the meaning specified in Section 501
of this Supplemental Indenture.

               "Underwriters" means Salomon Smith Barney Inc., Credit Suisse
First Boston and Morgan Stanley Dean Witter Co., Inc.

               "Underwriting Agreement" means the Underwriting Agreement dated
June ___, 2001, among the Company and the Underwriters.

               "Uniform Commercial Code" means the New York Uniform Commercial
Code as in effect from time to time.

               "Unrestricted Subsidiary" means (1) any Subsidiary of the Company
that at the time of determination shall be an Unrestricted Subsidiary (as
designated by the Board of Directors as provided below) and (2) any Subsidiary
of an Unrestricted Subsidiary. The Board of Directors may designate (a
"Designation") any Subsidiary of the Company (other than a Subsidiary that owns
any Capital Stock of, or owns, or holds any Lien on, any property of the



                                       20
<PAGE>   25

Company or any other Subsidiary of the Company that is not a Subsidiary of the
Subsidiary to be so designated) to be an Unrestricted Subsidiary if (a) no
Default shall have occurred and be continuing at the time of or after giving
effect to such Designation; (b) the Company could make an Investment (other than
a Permitted Investment) at the time of such Designation (assuming the
effectiveness thereof) in an amount (the "Designation Amount") equal to the Fair
Market Value of the Capital Stock of such Subsidiary on such date; and (c) the
Company could incur $1.00 of additional Indebtedness under the first sentence of
the covenant described in Section 605 of this Supplemental Indenture at the time
of such Designation (assuming the effectiveness thereof). The Board of Directors
may revoke (a "Revocation") any Designation of a Subsidiary as an Unrestricted
Subsidiary if (1) no Default shall have occurred and be continuing at the time
of and after giving effect to such Revocation; (2) the Company could incur $1.00
of additional Indebtedness under the first sentence of the covenant described in
Section 605 of this Supplemental Indenture at the time of such Revocation
(assuming the effectiveness thereof); and (3) all Liens and Indebtedness of such
Unrestricted Subsidiary outstanding immediately following such Revocation would,
if incurred at such time, have been permitted to be incurred under the
indenture. Any Designation or Revocation must be evidenced by a Board Resolution
certifying compliance with the foregoing provisions.

               In the event of any such Designation, the Company shall be deemed
to have made an Investment constituting a Restricted Payment pursuant to the
covenant described in Section 606 of this Supplemental Indenture for all
purposes of the indenture in the Designation Amount. The Company shall not, and
shall not permit any Restricted Subsidiary to, at any time (1) provide a
Guarantee of any Indebtedness of any Unrestricted Subsidiary; (2) be directly or
indirectly liable for any Indebtedness of any Unrestricted Subsidiary; or (3) be
directly or indirectly liable for any Indebtedness which provides that the
holder thereof may (upon notice, lapse of time or both) declare a default
thereon or cause the payment thereof to be accelerated or payable prior to its
final scheduled maturity upon the occurrence of a default with respect to any
Indebtedness of any Unrestricted Subsidiary (including any right to take
enforcement action against such Unrestricted Subsidiary), except to the extent
permitted under Section 606 of this Supplemental Indenture.

               "Voting Stock" of a Person means Capital Stock of such Person of
the class or classes pursuant to which the holders thereof have the general
voting power under ordinary circumstances to elect at least a majority of the
board of directors, managers or trustees of such Person (irrespective of whether
or not at the time stock of any other class or classes shall have or might have
voting power by reason of the happening of any contingency).

               "Weighted Average Life to Maturity" means, when applied to any
Indebtedness at any date, the number of years obtained by dividing (1) the sum
of the products obtained by multiplying (a) the amount of each then remaining
installment, sinking fund, serial maturity or other required scheduled payment
of principal, including payment at final maturity, in respect thereof, with (b)
the number of years (calculated to the nearest one-twelfth) that will elapse
between such date and the making of such payment, by (2) the then outstanding
aggregate principal amount of such Indebtedness.



                                       21
<PAGE>   26

SECTION 102. Conflicts with Base Indenture.

               Should any provision of this Supplemental Indenture limit,
qualify or conflict with another provision of the Base Indenture, such provision
of this Supplemental Indenture shall control.

                                   ARTICLE II

                                  FORM OF NOTES

SECTION 201. Form of Notes.

               The Notes shall be substantially in the form of Exhibit A hereto
which is hereby incorporated in and expressly made a part of this Indenture.

                                   ARTICLE III

                                    THE NOTES

SECTION 301. Title and Terms.

               This Series of Securities shall be known and designated as the
"Zero Coupon Convertible Senior Notes Due 2021" of the Company with a Stated
Maturity on June ____, 2021.

               The aggregate Principal Amount at Maturity of Notes which may be
authenticated and delivered under this Supplemental Indenture is limited to
$_____________ (subject to automatic increase by up to $__________ in the event
the Underwriters exercise the over-allotment option granted to them in the
Underwriting Agreement), except for replacement Notes authenticated and
delivered upon registration or transfer of, or in exchange for, or in lieu of,
other Notes pursuant to Section 306 of the Base Indenture.

               The Notes shall not bear interest, except as specified in Section
401 of this Supplemental Indenture. Original Issue Discount in the period during
which the Notes remain outstanding shall accrue at ____% per annum, on a
semi-annual bond equivalent basis using a 360-day year composed of twelve 30-day
months, from the Issue Date of the Notes.

               The Issue Price and Original Issue Discount accrued on the Notes
(or interest, if the Notes have been converted into semi-annual cash pay notes
pursuant to Section 401 of this Supplemental Indenture) shall be payable at the
office or agency of the Company in The City of New York maintained for such
purpose and at any other office or agency maintained by the Company for such
purpose; provided, however, that at the option of the Company payments may be
made by wire transfer or by check mailed to the address of the Person entitled
thereto as such address shall appear in the Security Register.

               The Notes shall not have the benefit of a sinking fund.



                                       22
<PAGE>   27

               The Notes shall rank pari passu with all other unsecured and
unsubordinated senior indebtedness, including borrowings under the Credit
Facility, of the Company.

SECTION 302. Registrar, Paying Agent and Conversion Agent.

               The Company shall maintain an office or agency where Notes may be
presented for registration of transfer or for exchange (the "Registrar"), an
office or agency where Notes may be presented for payment (the "Paying Agent")
and an office or agency where Notes may be presented for conversion (the
"Conversion Agent"). The Registrar shall keep a register of the Notes and of
their transfer and exchange. The Company may have one or more co-registrars, one
or more additional paying agents and one or more additional conversion agents.
The term "Paying Agent" includes any additional paying agent, the term
"Registrar" includes any co-registrars and the term "Conversion Agent" includes
any additional conversion agents. The Company initially appoints the Trustee as
(i) Registrar, Paying Agent and Conversion Agent in connection with the Notes
and (ii) the Securities Custodian with respect to the Global Notes.

               The Company shall enter into an appropriate agency agreement with
any Registrar, Paying Agent or Conversion Agent not a party to this Indenture,
which shall incorporate the terms of the Trust Indenture Act. The agreement
shall implement the provisions of this Indenture that relate to such agent. The
Company shall notify the Trustee of the name and address of any such agent. If
the Company fails to maintain a Registrar, Paying Agent or Conversion Agent, the
Trustee shall act as such and shall be entitled to appropriate compensation
therefor pursuant to Section 607 of the Base Indenture. The Company or any of
its domestically organized Restricted Subsidiaries may act as Paying Agent,
Registrar or Conversion Agent.

               The Company may remove any Registrar, Paying Agent or Conversion
Agent upon written notice to such Registrar, Paying Agent or Conversion Agent
and to the Trustee; provided, however, that no such removal shall become
effective until (1) acceptance of an appointment by a successor as evidenced by
an appropriate agreement entered into by the Company and such successor
Registrar, Paying Agent or Conversion Agent, as the case may be, and delivered
to the Trustee or (2) notification to the Trustee that the Trustee shall serve
as Registrar, Paying Agent or Conversion Agent until the appointment of a
successor in accordance with clause (1) above. The Registrar, Paying Agent or
Conversion Agent may resign at any time upon written notice; provided, however,
that the Trustee may resign as Registrar, Paying Agent or Conversion Agent only
if the Trustee also resigns as Trustee in accordance with Section 610 of the
Base Indenture.

SECTION 303. Purchase of Notes at Option of the Company; Notice to Trustee.

               Prior to June ___, 2004, Notes will not be redeemable. Beginning
on June ___, 2004, the Company, at its option, may elect to redeem Notes in
accordance with the provisions thereof and of the Indenture. If the Company
elects to redeem Notes, it shall notify the Trustee in writing of the Redemption
Date, the Principal Amount at Maturity of Notes to be redeemed and the
Redemption Price.

               The Company shall give each notice to the Trustee provided for in
this Section 303 at least 45 days before the Redemption Date unless the Trustee
consents to a shorter period.



                                       23
<PAGE>   28

Such notice shall be accompanied by an Officers' Certificate and an Opinion of
Counsel from the Company to the effect that such redemption will comply with the
conditions herein. If fewer than all the Notes are to be redeemed, the record
date relating to such redemption shall be selected by the Company and given to
the Trustee, which record date shall be not fewer than 15 days after the date of
notice to the Trustee. Any such notice may be canceled at any time prior to
notice of such redemption being mailed to any Holder and shall thereby be void
and of no effect.

SECTION 304. Selection of Notes to be Redeemed.

               If fewer than all the Notes are to be redeemed, the Trustee shall
select the Notes to be redeemed by any method that complies with applicable
legal and securities exchange requirements, if any, and that the Trustee in its
sole discretion shall deem to be fair and appropriate and in accordance with
methods generally used at the time of selection by fiduciaries in similar
circumstances. The Trustee shall make the selection at least 30 days but no more
than 60 days before the Redemption Date from outstanding Notes not previously
called for redemption. Notes and portions thereof that the Trustee selects shall
be in Principal Amounts at Maturity of $1,000 or integral multiples of $1,000.
Provisions of this Indenture that apply to Notes called for redemption also
applies to portions of Notes called for redemption. The Trustee shall promptly
notify the Company of the Notes (or portions thereof) to be redeemed.

               If any Note selected for partial redemption is converted in part
after such selection, the converted portion of such Note shall be deemed (so far
as may be) to be the portion to be selected for redemption. The Notes (or
portions thereof) so selected shall be deemed duly selected for redemption for
all purposes hereof, notwithstanding that any such Note is converted in whole or
in part before the mailing of the notice of redemption. Upon any redemption of
less than all the Notes, the Company and the Trustee may, solely for the
purposes of this Section 304, treat as outstanding any Notes surrendered for
conversion during the period 15 days next preceding the mailing of a notice of
redemption and need not treat as outstanding any Note authenticated and
delivered during such period in exchange for the unconverted portion of any Note
converted in part during such period.

SECTION 305. Notice of Redemption.

               At least 30 days but not more than 60 days before a date for
redemption of Notes, the Company shall mail a notice of redemption by
first-class mail to each Holder of Notes to be redeemed at such Holder's
registered address and to the Trustee, release such notice to the Reuters and
Bloomberg news services and publish a copy of such notice in The Wall Street
Journal (or, if The Wall Street Journal is not published at that time, another
newspaper of national circulation).

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

               (1) the Redemption Date;

               (2) the Redemption Price;

               (3) the Conversion Rate applicable on the Redemption Date;



                                       24
<PAGE>   29

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

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

               (6) that Notes called for redemption may be converted at any time
before the close of business on the Business Day immediately preceding the
Redemption Date;

               (7) that Holders who want to convert Notes must satisfy the
requirements set forth therein and in this Indenture;

               (8) if fewer than all the outstanding Notes are to be redeemed,
the certificate numbers, if the Notes are in certificated form and Principal
Amounts at Maturity of the particular Notes to be redeemed;

               (9) that, unless the Company defaults in making payment of such
Redemption Price or the Paying Agent is prohibited from making such payment
pursuant to the terms of this Indenture, Original Issue Discount on Notes (or
portion thereof) called for redemption (or interest, if the Notes have been
converted into semi-annual cash pay notes pursuant to Section 401) ceases to
accrue on and after the Redemption Date;

               (10) the CUSIP or ISIN number, if any, printed on the Notes being
redeemed; and

               (11) that no representation is made as to the correctness or
accuracy of the CUSIP or ISIN 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 as provided to it in the Company's name and at the Company's expense.
In such event, the Company shall provide the Trustee with the information
required by this Section 305.

SECTION 306. Effect of Notice of Redemption.

               Once notice of redemption is mailed, Notes called for redemption
become due and payable on the Redemption Date and at the Redemption Price stated
in the notice except for Notes that are converted in accordance with the terms
of this Indenture. Upon surrender to the Paying Agent, such Notes shall be paid
at the Redemption Price stated in the notice; provided, however, that if Notes
have been converted into semi-annual cash pay notes pursuant to Section 401 of
this Supplemental Indenture and the Redemption Date is after a Regular Record
Date and on or prior to the Interest Payment Date, the accrued interest shall be
payable to the Holder of the redeemed semi-annual cash pay notes registered on
the relevant Regular Record Date.

               Failure to give notice or any defect in the notice to any Holder
shall not affect the validity of the notice to any other Holder.



                                       25
<PAGE>   30

SECTION 307. Deposit of Redemption Price.

               Prior to 11:00 a.m. (New York City time) on the Redemption Date,
the Company shall deposit with the Paying Agent (or, if the Company or a
Subsidiary of the Company is the Paying Agent, shall segregate and hold in
trust) U.S. dollars in immediately available funds sufficient to pay the
Redemption Price of all Notes to be redeemed on that date, other than Notes or
portions of Notes called for redemption that have been delivered by the Company
to the Trustee for cancellation or Notes that have been converted. The Paying
Agent shall as promptly as practicable return to the Company any money, not
required for that purpose because of conversion of Notes pursuant to Article V
of this Supplemental Indenture. If such money is then held by the Company in
trust and is not required for such purpose it shall be discharged from such
trust. The Company at any time may require a Paying Agent to pay all money held
by it to the Trustee and to account for any funds disbursed by the Paying Agent.
Upon complying with this Section 307, the Paying Agent shall have no further
liability for the money delivered to the Trustee.

SECTION 308. Notes Redeemed in Part.

               Upon surrender of a Note that is redeemed in part, the Company
shall execute and the Trustee shall authenticate for the Holder (at the
Company's expense) a new Note equal in Principal Amount at Maturity to the
unredeemed portion of the Note surrendered.

SECTION 309. Conversion Arrangement on Call for Redemption.

               In connection with any redemption of Notes, the Company may
arrange for the purchase and conversion of any Notes called for redemption by an
agreement with one or more investment banks or other purchasers to purchase such
Notes by paying to the Trustee in trust for the Holders, on or prior to 11:00
a.m. (New York City time) on the Redemption Date, an amount that, together with
any amounts deposited with the Trustee by the Company for the redemption of such
Notes, is not less than the Redemption Price of such Notes. Notwithstanding
anything to the contrary contained in this Article III, the obligation of the
Company to pay the Redemption Price of such Notes shall be deemed to be
satisfied and discharged to the extent such amount is so paid by such
purchasers. If such an agreement is entered into, any Notes not duly surrendered
for conversion by the Holders thereof may, at the option of the Company, be
deemed, to the fullest extent permitted by law, acquired by such purchasers from
such Holders and (notwithstanding anything to the contrary contained in Article
V of this Supplemental Indenture) surrendered by such purchasers for conversion,
all as of immediately prior to the close of business on the Business Day prior
to the Redemption Date, subject to payment of the above amount as aforesaid. The
Trustee shall hold and pay to the Holders whose Notes are selected for
redemption any such amount paid to it for purchase and conversion in the same
manner as it would moneys deposited with it by the Company for the redemption of
Notes. Without the Trustee's prior written consent, no arrangement between the
Company and such purchasers for the purchase and conversion of any Notes shall
increase or otherwise affect any of the powers, duties, responsibilities or
obligations of the Trustee as set forth in this Indenture, and the Company
agrees to indemnify the Trustee from, and hold it harmless against, any loss,
liability or expense arising out of or in connection with any such arrangement
for the purchase and conversion of any Notes between the Company and such
purchasers, including the costs and



                                       26
<PAGE>   31

expenses incurred by the Trustee in the defense of any claim or liability
arising out of or in connection with the exercise or performance of any of its
powers, duties, responsibilities or obligations under this Indenture; provided
that the Company shall not be obligated to indemnify the Trustee for any loss,
liability or expenses arising out of the Trustee's gross negligence or willful
misconduct.

SECTION 310. Purchase of Notes at Option of the Holder.

               (a) General. Notes shall be purchased by the Company pursuant to
the terms thereof as of June ___, 2004, June ___, 2007, June ___, 2010, June
___, 2013 and June ___, 2016 (each, a "Purchase Date"), at the purchase price of
$______ per $1,000 of Principal Amount at Maturity as of June ___, 2004, $______
per $1,000 of Principal Amount at Maturity as of June ___, 2007, $______ per
$1,000 of Principal Amount at Maturity as of June ___, 2010, $______ per $1,000
of Principal Amount at Maturity as of June ___, 2013 and $______ per $1,000 of
Principal Amount at Maturity as of June ___, 2016 (each, a "Purchase Price", as
applicable, provided that, if prior to a Purchase Date the Notes have been
converted to semi-annual cash pay notes following the occurrence of a Tax Event,
the Purchase Price will be equal to the Restated Principal Amount plus accrued
and unpaid interest to the Purchase Date), at the option of the Holder thereof,
upon:

               (1) delivery to the Paying Agent by the Holder of a written
notice of purchase (a "Purchase Notice"), substantially in the form of Exhibit B
hereto, at any time from the opening of business on the date that is 20 Business
Days prior to a Purchase Date until the close of business on such Purchase Date
stating:

               (A) the certificate numbers of the Notes which the Holder will
        deliver to be purchased, if the Notes are in certificated form,

               (B) the portion of the Principal Amount at Maturity of the Note
        which the Holder will deliver to be purchased, which portion must be in
        a Principal Amount at Maturity of $1,000 or integral multiples thereof,

               (C) that such Note shall be purchased as of the Purchase Date
        pursuant to the terms and conditions specified in the Notes and in this
        Indenture, and

               (D) that for any Notes purchased on or after _________, 2007, in
        the event the Company elects, pursuant to Section 310(b) of this
        Supplemental Indenture, to pay the Purchase Price to be paid as of such
        Purchase Date, in whole or in part, in shares of Common Stock but such
        portion of the Purchase Price shall ultimately be payable to such Holder
        entirely in cash because any of the conditions to payment of the
        Purchase Price in Common Stock is not satisfied prior to the close of
        business on such Purchase Date, as set forth in Section 310(d) of this
        Supplemental Indenture, whether such Holder elects (i) to withdraw such
        Purchase Notice as to some or all of the Notes to which such Purchase
        Notice relates (stating the Principal Amount at Maturity and certificate
        numbers of the Notes as to which such withdrawal shall relate), or (ii)
        to receive cash in respect of the entire Purchase Price for all Notes
        (or portions thereof) to which such Purchase Notice relates; and



                                       27
<PAGE>   32

               (2) book-entry transfer or delivery of such Note to the Paying
Agent for cancellation prior to, on or after the Purchase Date (together with
all necessary endorsements) at the offices of the Paying Agent, such transfer or
delivery being a condition to receipt by the Holder of the Purchase Price
therefor; provided, however, that such Purchase Price shall be so paid pursuant
to this Section 310 only if the Note so transferred or delivered to the Paying
Agent shall conform in all respects to the description thereof in the related
Purchase Notice;

               If a Holder, in such Holder's Purchase Notice, fails to indicate
such Holder's choice with respect to the election set forth in clause (D) of
Section 310(a)(1), such Holder will be deemed to have elected to receive cash in
respect of the Purchase Price for all Notes subject to such Purchase Notice in
the circumstances set forth in such clause (D).

               The Company shall purchase from the Holder thereof, pursuant to
this Section 310, a portion of a Note if the Principal Amount at Maturity of
such portion is $1,000 or an integral multiple of $1,000 if so requested by the
Holder. Provisions of this Indenture that apply to the purchase of all of a Note
also apply to the purchase of such portion of such Note.

               Any purchase by the Company contemplated pursuant to the
provisions of this Section 310 shall be consummated by the delivery of the
consideration to be received by the Holder promptly following the later of the
Purchase Date and the time of delivery of the Note.

               Notwithstanding anything herein to the contrary, any Holder
delivering to the Paying Agent a Purchase Notice contemplated by this Section
310(a) shall have the right to withdraw such Purchase Notice at any time prior
to the close of business on the Purchase Date by delivery of a written notice of
withdrawal to the Paying Agent in accordance with Section 312 of this
Supplemental Indenture.

               The Paying Agent shall promptly notify the Company of the receipt
by it of any Purchase Notice or written notice of withdrawal thereof.

               (b) Company's Right to Elect Manner of Payment of Purchase Price.
The Company will pay the Purchase Price for any Notes purchased on _________,
2004, made pursuant to Section 310(a) of this Supplemental Indenture, in cash.
For any Notes purchased on or after _________, 2007, made pursuant to Section
310(a) of this Supplemental Indenture, the Company may elect to pay all or a
portion of the Purchase Price in shares of Common Stock, so long as the Common
Stock is then listed on a national securities exchange or traded on the NASDAQ
National Market System. If the Company elects to pay the Purchase Price, in
whole or in part, in shares of Common Stock, the number of shares of Common
Stock to be delivered by the Company will be equal to the portion of the
Purchase Price to be paid in Common Stock divided by 97.5% of the Market Price,
subject to the conditions set forth in Sections 310(c) and (d) of this
Supplemental Indenture. The Company shall designate, in the Company's Notice
delivered pursuant to Section 310(e) of this Supplemental Indenture, whether the
Company will purchase the Notes for cash or Common Stock, or, if a combination
thereof, the percentages of the Purchase Price of Notes in respect of which it
will pay in cash or Common Stock; provided that the Company will pay cash for
fractional interests in Common Stock. For purposes of determining the existence
of potential fractional interests, all Notes subject to purchase by the Company
held by a Holder shall be considered together (no matter how many separate



                                       28
<PAGE>   33

certificates are to be presented). Each Holder whose Notes are purchased
pursuant to this Section 310 shall receive the same percentage of cash or Common
Stock in payment of the Purchase Price for such Notes, except (i) as provided in
Section 310(d) of this Supplemental Indenture with regard to the payment of cash
in lieu of fractional shares of Common Stock and (ii) in the event that the
Company is unable to purchase the Notes of a Holder or Holders for Common Stock
because any necessary qualifications or registrations of the Common Stock under
applicable state securities laws cannot be obtained, the Company may purchase
the Notes of such Holder or Holders for cash. The Company may not change its
election with respect to the consideration (or components or percentages of
components thereof) to be paid once the Company has given the Company's Notice
to Holders except pursuant to this Section 310(b) or pursuant to Section 310(d)
in the event of a failure to satisfy, prior to the close of business on the
Purchase Date, any condition to the payment of the Purchase Price, in whole or
in part, in Common Stock.

               If the Company elects to pay all or part of the Purchase Price in
Common Stock, the portion of accrued Original Issue Discount (or interest, if
the Notes have been converted into semi-annual cash pay notes pursuant to
Section 401 of this Supplemental Indenture) attributable to the period from the
Issue Date (or, if the Company has exercised the option to convert the Notes
into semi-annual cash pay notes pursuant to Section 401 of this Supplemental
Indenture, the later of (x) the date of such exercise, and (y) the date on which
interest was last paid) through the Purchase Date with respect to the
surrendered Note shall not be cancelled, extinguished or forfeited, but rather
shall be deemed to be paid in full to the Holder thereof through the delivery of
the Common Stock (together with a cash payment, if any, in lieu of fractional
shares) and cash, if any, in exchange for the Note being purchased pursuant to
the terms hereof; and such cash, if any, and the fair market value of such
shares of Common Stock (together with any such cash payment in lieu of
fractional shares) shall be treated as delivered pro rata, to the extent
thereof, first in exchange for Original Issue Discount (or interest, if the
Notes have been converted into semi-annual cash pay notes pursuant to Section
401 of this Supplemental Indenture) accrued to the Purchase Date, and the
balance, if any, of such cash and the fair market value of such Common Stock
(and any such cash payment) shall be treated as delivered in exchange for the
Issue Price of the Note being purchased pursuant to the provisions hereof.

               At least three Business Days before the Company's Notice Date,
the Company shall deliver an Officers' Certificate to the Trustee specifying:

               (i) the manner of payment selected by the Company,

               (ii) the information required by Section 310(e) of this
        Supplemental Indenture,

               (iii) if the Company elects to pay the Purchase Price, or a
        specified percentage thereof, in Common Stock, that the conditions to
        such manner of payment set forth in Section 310(d) of this Supplemental
        Indenture have been or will be complied with, and

               (iv) whether the Company desires the Trustee to give the
        Company's Notice required by Section 310(e) of this Supplemental
        Indenture.



                                       29
<PAGE>   34

               (c) Purchase with Cash. Except for _________, 2004, on each
Purchase Date, at the option of the Company, the Purchase Price of Notes in
respect of which a Purchase Notice pursuant to Section 310(a) of this
Supplemental Indenture has been given, or a specified percentage thereof, may be
paid by the Company with cash equal to the aggregate Purchase Price or such
percentage of the aggregate Purchase Price of such Notes. All Notes purchased on
________, 2004, pursuant to Section 310(a) of this Supplemental Indenture, will
be paid in cash.

               (d) Payment by Issuance of Common Stock. Except for _________,
2004, on each Purchase Date, at the option of the Company, the Purchase Price of
Notes in respect of which a Purchase Notice pursuant to Section 310(a) of this
Supplemental Indenture has been given, or a specified percentage thereof, may be
paid by the Company by the issuance of a number of shares of Common Stock equal
to the quotient obtained by dividing (i) the amount of cash to which the Holders
would have been entitled had the Company elected to pay all or such specified
percentage, as the case may be, of the Purchase Price of such Notes in cash by
(ii) 0.975 times the Market Price of a share of Common Stock, subject to the
next succeeding paragraph. All Notes purchased on ________, 2004, pursuant to
Section 310(a) of this Supplemental Indenture, will be paid in cash.

               The Company will not issue a fractional share of Common Stock in
payment of the Purchase Price. Instead the Company will pay cash for the current
market value of the fractional share. The current market value of a fraction of
a share shall be determined, to the nearest 1/1,000th of a share, by multiplying
the Market Price by such fraction and rounding the product to the nearest whole
cent. It is understood that if a Holder elects to have more than one Note
purchased, the number of shares of Common Stock shall be based on the aggregate
amount of Notes to be purchased.

               The Company's right to exercise its election to purchase the
Notes pursuant to Section 310 of this Supplemental Indenture through the
issuance by the Company of shares of Common Stock shall be conditioned upon:

               (i) the Company not having given its Company's Notice of an
        election to pay entirely in cash and its timely giving of its Company's
        Notice of election to purchase all or a specified percentage of the
        Notes with Common Stock as provided herein;

               (ii) the registration of the shares of Common Stock to be issued
        in respect of the payment of the Purchase Price under the Securities Act
        or the Exchange Act, in each case if required;

               (iii) any necessary qualification or registration under
        applicable state securities laws or the availability of an exemption
        from such qualification and registration; and

               (iv) the receipt by the Trustee of an Officers' Certificate and
        an Opinion of Counsel, each stating that (A) the terms of the issuance
        of the Common Stock are in conformity with this Indenture and (B) the
        shares of Common Stock to be issued by the Company in payment of the
        Purchase Price in respect of Notes have been duly authorized and, when
        issued and delivered pursuant to the terms of this Indenture in payment
        of the Purchase Price in respect of the Notes, will be validly issued,
        fully paid and non-



                                       30
<PAGE>   35

        assessable and, to the best of such counsel's knowledge, free from
        preemptive rights, and, in the case of such Officers' Certificate,
        stating that conditions (i), (ii) and (iii) above and the condition set
        forth in the second succeeding sentence have been satisfied and, in the
        case of such Opinion of Counsel, stating that condition (ii) above has
        been satisfied.

               Such Officers' Certificate shall also set forth the number of
shares of Common Stock to be issued for each $1,000 Principal Amount at Maturity
of Notes and the Sale Price of a share of Common Stock on each trading day
during the period during which the Market Price is calculated. The Company may
pay the Purchase Price (or any portion thereof) in Common Stock only if the
information necessary to calculate the Market Price is published in a daily
newspaper of national circulation. If the foregoing conditions are not satisfied
with respect to a Holder or Holders prior to the close of business on the
Purchase Date and the Company has elected to purchase the Notes pursuant to this
Section 310 of this Supplemental Indenture through the issuance by the Company
of shares of Common Stock, the Company shall pay the entire Purchase Price of
the Notes of such Holder or Holders in cash.

               The "Market Price" means the average of the Sale Prices of the
Common Stock for the 20 trading day period ending on the third Business Day (if
the third Business Day prior to the applicable Purchase Date is a trading day,
or if not, then on the last trading day prior to such third Business Day) prior
to the applicable Purchase Date, appropriately adjusted to take into account the
occurrence, during the period commencing on the first of such trading days
during such 20 trading day period and ending on such Purchase Date, of any event
described in Section 506, 507 or 508 of this Supplemental Indenture; subject,
however, to the conditions set forth in Sections 509 and 512 of this
Supplemental Indenture.

               The "Sale Price" of the Common Stock on any date means the
closing sale price per share (or, if no closing sale price is reported, the
average of the bid and ask prices or, if more than one in either case, the
average of the average bid and average ask prices) on such date as reported in
the composite transactions for the principal United States securities exchange
on which the Common Stock is traded or, if the Common Stock is not listed on a
United States national or regional securities exchange, as reported by the
National Association of Notes Dealers Automated Quotation National Market
System.

               (e) Notice of Election. In the event the Company has elected to
pay the Purchase Price with cash or Common Stock or any combination thereof
pursuant to Section 310(b) of this Supplemental Indenture, the Company's notice
of election shall be sent to the Holders (and to beneficial owners as required
by applicable law) in the manner provided herein (the "Company's Notice"). The
Company's Notice shall be sent to Holders (and to beneficial owners as required
by applicable law) not less than 20 Business Days prior to such Purchase Date
(the "Company's Notice Date"). The Company's Notice shall state the manner of
payment elected and shall contain the following information:

               (1) state that each Holder will receive Common Stock in respect
of the specified percentage of the Purchase Price of the Notes held by such
Holder (except any cash amount to be paid in lieu of fractional shares);



                                       31
<PAGE>   36

               (2) state that the total number of shares of Common Stock to be
issued to Holders will be equal to the quotient obtained by dividing (i) the
amount of cash to which the Holders would have been entitled had the Company
elected to pay all or such specified percentage, as the case may be, of the
Purchase Price of such Notes in cash by (ii) 0.975 times the Market Price of a
share of Common Stock;

               (3) set forth the method of calculating the Market Price of the
Common Stock; and

               (4) state that because the Market Price of Common Stock will be
determined prior to the Purchase Date, Holders will bear the market risk with
respect to the value of the Common Stock to be received from the date such
Market Price is determined to the Purchase Date.

               In any case, each Company's Notice shall include a form of
Purchase Notice to be completed by a Holder and shall state:

               (1) the Purchase Price and the Conversion Rate applicable on the
Company's Notice Date and any adjustment thereto;

               (2) the name and address of the Paying Agent and the Conversion
Agent;

               (3) that Notes as to which a Purchase Notice has been given may
be converted pursuant to Article V of this Supplemental Indenture hereof only if
the applicable Purchase Notice has been withdrawn in accordance with the terms
of this Indenture;

               (4) that Notes must be surrendered to the Paying Agent for
cancellation to collect payment;

               (5) that the Purchase Price for any Note as to which a Purchase
Notice has been given and not withdrawn will be paid promptly following the
later of the Purchase Date and the time of surrender of such Note as described
in (4);

               (6) the procedures the Holder must follow to exercise rights
under this Section 310 of this Supplemental Indenture and a brief description of
those rights;

               (7) briefly, the conversion rights of the Notes;

               (8) the procedures for withdrawing a Purchase Notice (including,
without limitation, for a conditional withdrawal pursuant to the terms of
Section 310(a)(1)(D) or Section 312 of this Supplemental Indenture);

               (9) that, unless the Company defaults in making payment of such
Purchase Price, Original Issue Discount on Notes covered by any Purchase Notice
(or interest, if the Notes have been converted into semi-annual cash pay notes
pursuant to Section 401 of this Supplemental Indenture), if any, will cease to
accrue on and after the Purchase Date; and

               (10) the CUSIP or ISIN number of the Notes.



                                       32
<PAGE>   37

               At the Company's request, the Trustee shall give such Company's
Notice in the name of the Company and at the Company's expense; provided,
however, that, in all cases, the text of such Company's Notice shall be prepared
by the Company.

               (f) Covenants of the Company. All shares of Common Stock
delivered upon purchase of the Notes shall be newly issued shares or treasury
shares, shall be duly authorized, validly issued, fully paid and nonassessable,
and shall be free from preemptive rights and free of any lien or adverse claim.

               The Company shall use its best efforts to list or cause to have
quoted any shares of Common Stock to be issued to purchase Notes on each
national securities exchange or over-the-counter or other domestic market on
which the Common Stock is then listed or quoted.

               (g) Procedure upon Purchase. The Company shall deposit cash (in
respect of a cash purchase under Section 310(c) of this Supplemental Indenture
or for fractional shares, as applicable) or shares of Common Stock, or a
combination thereof, as applicable, at the time and in the manner as provided in
Section 313 of this Supplemental Indenture, sufficient to pay the aggregate
Purchase Price of all Notes to be purchased pursuant to this Section 310. As
soon as practicable after the Purchase Date, the Company shall deliver to each
Holder entitled to receive Common Stock through the Stock Transfer Agent, a
certificate for the number of full shares of Common Stock issuable in payment of
the Purchase Price. The Person in whose name the certificate for Common Stock is
registered shall be treated as a holder of record of shares of Common Stock on
the Business Day following the Purchase Date. Subject to Section 310(d) of this
Supplemental Indenture, no payment or adjustment will be made for dividends on
any Common Stock delivered in payment of the Purchase Price the record date for
which occurred on or prior to the Purchase Date.

               (h) Taxes. If a Holder of a Note is paid in Common Stock, the
Company shall pay any documentary, stamp or similar issue or transfer tax due on
such issue of shares of Common Stock. However, the Holder shall pay any such tax
which is due because the Holder requests the shares of Common Stock to be issued
in a name other than the Holder's name. The Paying Agent may refuse to deliver
the certificates representing the Common Stock being issued in a name other than
the Holder's name until the Paying Agent receives a sum that the Company deems
to be sufficient to pay any tax which will be due because the shares of Common
Stock are to be issued in a name other than the Holder's name. Nothing herein
shall preclude any income tax withholding required by law or regulations.

SECTION 311. Repurchase of Notes at Option of the Holder upon Fundamental
Change.

               (a) General. If there shall have occurred a Fundamental Change
prior to ______, 2004, Notes shall be purchased by the Company, at a purchase
price (the "Fundamental Change Repurchase Price") equal to the Issue Price plus
accrued Original Issue Discount to the first Business Day (the "Fundamental
Change Repurchase Date") following the 60th day after the Fundamental Change
Notice Date, at the option of the Holder thereof, upon:

               (1) delivery to the Paying Agent by the Holder of a written
notice of purchase (a "Fundamental Change Repurchase Notice"), substantially in
the form of Exhibit C hereto, at



                                       33
<PAGE>   38

any time from the opening of business on the date that is 30 days prior to a
Fundamental Change Repurchase Date until the close of business on such
Fundamental Change Repurchase Date stating:

               (A) the certificate numbers of the Notes which the Holder will
        deliver to be purchased, if the Notes are in certificated form,

               (B) the portion of the Principal Amount at Maturity of the Note
        which the Holder will deliver to be purchased, which portion must be in
        a Principal Amount at Maturity of $1,000 or integral multiples thereof,

               (C) that such Note shall be purchased as of the Fundamental
        Change Repurchase Date pursuant to the terms and conditions specified in
        the Notes and in this Indenture, and

               (D) that for Fundamental Change repurchases made prior to October
        31, 2002, in the event the Company elects, pursuant to Section 311(b) of
        this Supplemental Indenture, to pay the Fundamental Change Repurchase
        Price to be paid as of such Fundamental Change Repurchase Date, in whole
        or in part, in shares of Common Stock but such portion of the
        Fundamental Change Repurchase Price shall ultimately be payable to such
        Holder entirely in cash because any of the conditions to payment of the
        Fundamental Change Repurchase Price in Common Stock is not satisfied
        prior to the close of business on such Fundamental Change Repurchase
        Date, as set forth in Section 311(d) of this Supplemental Indenture,
        whether such Holder elects (i) to withdraw such Fundamental Change
        Repurchase Notice as to some or all of the Notes to which such
        Fundamental Change Repurchase Notice relates (stating the Principal
        Amount at Maturity and certificate numbers of the Notes as to which such
        withdrawal shall relate), or (ii) to receive cash on or before November
        30, 2002 and any accrued interest thereon in respect of the entire
        Fundamental Change Repurchase Price for all Notes (or portions thereof)
        to which such Fundamental Change Repurchase Notice relates; and

               (2) book-entry transfer or delivery of such Note to the Paying
Agent for cancellation prior to, on or after the Fundamental Change Repurchase
Date (together with all necessary endorsements) at the offices of the Paying
Agent, such delivery being a condition to receipt by the Holder of the
Fundamental Change Repurchase Price therefor; provided, however, that such
Fundamental Change Repurchase Price shall be so paid pursuant to this Section
311 only if the Note so delivered to the Paying Agent shall conform in all
respects to the description thereof in the related Fundamental Change Repurchase
Notice.

               If a Holder, in such Holder's Fundamental Change Repurchase
Notice, fails to indicate such Holder's choice with respect to the election set
forth in clause (D) of Section 311(a)(1) of this Supplemental Indenture, such
Holder will be deemed to have elected to receive cash in respect of the
Fundamental Change Repurchase Price for all Notes subject to such Fundamental
Change Repurchase Notice in the circumstances set forth in such clause (D).

               The Company shall purchase from the Holder thereof, pursuant to
this Section 311, a portion of a Note if the Principal Amount at Maturity of
such portion is $1,000 or



                                       34
<PAGE>   39

an integral multiple of $1,000 if so requested by the Holder. Provisions of this
Indenture that apply to the purchase of all of a Note also apply to the purchase
of such portion of such Note.

               Any purchase by the Company contemplated pursuant to the
provisions of this Section 311 shall be consummated by the delivery of the
consideration to be received by the Holder promptly following the later of the
Fundamental Change Repurchase Date and the time of delivery of the Note.

               Notwithstanding anything herein to the contrary, any Holder
delivering to the Paying Agent a Fundamental Change Repurchase Notice
contemplated by this Section 311(a) shall have the right to withdraw such
Fundamental Change Repurchase Notice at any time prior to the close of business
on the Fundamental Change Repurchase Date by delivery of a written notice of
withdrawal to the Paying Agent in accordance with Section 312 of this
Supplemental Indenture.

               The Paying Agent shall promptly notify the Company of the receipt
by it of any Fundamental Change Repurchase Notice or written notice of
withdrawal thereof.

               A "Fundamental Change" shall be deemed to have occurred at such
time as any of the following events shall occur:

               (i) the Company consolidates or merges with or into another
        Person and, immediately after giving effect to the merger or
        consolidation, less than 50% of the outstanding securities entitled to
        vote generally in the election of directors or persons who serve similar
        functions of the surviving or resulting entity are then beneficially
        owned (within the meaning of Rule 13d-3 under the Exchange Act) in the
        aggregate by the Company's stockholders immediately prior to such merger
        or consolidation, or if the record date has been set to determine the
        Company's stockholders entitled to vote on such merger or consolidation,
        the stockholders as of such record date;

               (ii) the Company sells, conveys, transfers or leases its
        properties and assets substantially as an entirety to any Person (other
        than a Subsidiary of the Company);

               (iii) the Common Stock is reclassified into, exchanged for or
        converted into the right to receive any other property or security,
        provided, that none of these circumstances will be a Fundamental Change
        of such property and securities, other than cash payments for fractional
        shares, consists of shares of voting Common Stock of the surviving
        Person that are, or upon issuance will be, traded on a United States
        national securities exchange or approved for trading on an established
        over-the-counter trading market in the United States; or

               (iv) any Person, including its Affiliates and associates (an
        "Acquiring Person"), files Schedule 13D or Schedule TO (or any successor
        schedule, form or report under the Exchange Act) disclosing that such
        Person has become the beneficial owner of 50% or more of the total
        voting power in the aggregate of all classes of the Common Stock then
        outstanding normally entitled to vote in elections of directors other
        than through a merger or binding share exchange in which all or
        substantially all of the consideration (except for cash payments for
        fractional shares) received by the holders



                                       35
<PAGE>   40

        (other than the Acquiring Person) of the Common Stock consists of shares
        of voting common stock of the surviving Person that are, or that upon
        issuance will be, traded on a United States national securities exchange
        or approved for trading on an established automated over-the-counter
        trading market in the United States.

               (b) Company's Right to Elect Manner of Payment of Fundamental
Change Repurchase Price. For any Fundamental Change repurchase made prior to
October 31, 2002, pursuant to Section 311(a) of this Supplemental Indenture, the
Company may elect to pay all or a portion of the Fundamental Change Repurchase
Price, in shares of Common Stock, so long as the Common Stock is then listed on
a national securities exchange or traded on the NASDAQ National Market System.
If the Common Stock does not meet the foregoing criteria as of such date, any
cash payment owing pursuant to the preceding sentence will be made on or before
November 30, 2002 and will accrue interest from the Conversion Date at a rate of
22 basis points above the three month London Interbank Offered Rate in effect
two Business days before the Conversion Date through the date of payment. If the
Company elects to pay the Fundamental Change Repurchase Price, in whole or in
part, in shares of Common Stock, the number of shares of common Stock to be
delivered by the Company will be equal to the portion of the Fundamental Change
Repurchase Price to be paid in Common Stock divided by 97.5% of the Market
Price, subject to the conditions set forth in Sections 311(c) and (d) of this
Supplemental Indenture. The Company shall designate, in the Fundamental Change
Notice delivered pursuant to Section 311(e) of this Supplemental Indenture,
whether the Company will purchase the Notes for cash or Common Stock, or, if a
combination thereof, the percentages of the Fundamental Change Repurchase Price
of Notes in respect of which it will pay in cash or Common Stock; provided that
the Company will pay cash for fractional interests in Common Stock. For purposes
of determining the existence of potential fractional interests, all Notes
subject to purchase by the Company held by a Holder shall be considered together
(no matter how many separate certificates are to be presented). Each Holder
whose Notes are purchased pursuant to this Section 311 shall receive the same
percentage of cash or Common Stock in payment of the Fundamental Change
Repurchase Price for such Notes, except (i) as provided in Section 311(d) of
this Supplemental Indenture with regard to the payment of cash in lieu of
fractional shares of Common Stock and (ii) in the event that the Company is
unable to purchase the Notes of a Holder or Holders for Common Stock because any
necessary qualifications or registrations of the Common Stock under applicable
state securities laws cannot be obtained, the Company may purchase the Notes of
such Holder or Holders for cash. The Company may not change its election with
respect to the consideration (or components or percentages of components
thereof) to be paid once the Company has given its Fundamental Change Notice to
Holders except pursuant to this Section 311(b) or pursuant to Section 311(d) of
this Supplemental Indenture in the event of a failure to satisfy, prior to the
close of business on the Fundamental Change Repurchase Date, any condition to
the payment of the Fundamental Change Repurchase Price, in whole or in part, in
Common Stock.

               If the Company elects to pay all or part of the Fundamental
Change Repurchase Price in Common Stock, the portion of accrued Original Issue
Discount (or interest, if the Notes have been converted into semi-annual cash
pay notes pursuant to Section 401 of this Supplemental Indenture) attributable
to the period from the Issue Date (or, if the Company has exercised the option
to convert the Notes into semi-annual cash pay notes pursuant to Section 401 of
this Supplemental Indenture, the later of (x) the date of such exercise, and (y)
the



                                       36
<PAGE>   41

date on which interest was last paid) to the Fundamental Change Repurchase Date
with respect to the surrendered Note shall not be cancelled, extinguished or
forfeited, but rather shall be deemed to be paid in full to the Holder thereof
through the delivery of the Common Stock (together with a cash payment, if any,
in lieu of fractional shares) and cash, if any, in exchange for the Note being
purchased pursuant to the terms hereof; and such cash, if any, and the fair
market value of such shares of Common Stock (together with any such cash payment
in lieu of fractional shares) shall be treated as delivered pro rata, to the
extent thereof, first in exchange for Original Issue Discount (or interest, if
the Notes have been converted into semi-annual cash pay notes pursuant to
Section 401 of this Supplemental Indenture) accrued to the Fundamental Change
Repurchase Date, and the balance, if any, of such cash and the fair market value
of such Common Stock (and any such cash payment) shall be treated as delivered
in exchange for the Issue Price of the Note being purchased pursuant to the
provisions hereof.

               At least three Business Days before the Fundamental Change Notice
Date, the Company shall deliver an Officers' Certificate to the Trustee
specifying:

               (i) the manner of payment selected by the Company,

               (ii) the information required by Section 311(e) of this
        Supplemental Indenture,

               (iii) if the Company elects to pay the Fundamental Change
        Repurchase Price, or a specified percentage thereof, in Common Stock,
        that the conditions to such manner of payment set forth in Section
        311(d) of this Supplemental Indenture have been or will be complied
        with, and

               (iv) whether the Company desires the Trustee to give the
        Fundamental Change Notice required by Section 311(e) of this
        Supplemental Indenture.

               (c) Purchase with Cash. For any Fundamental Change repurchase
occurring prior to October 31, 2002, at the option of the Company, the
Fundamental Change Repurchase Price of Notes in respect of which a Fundamental
Change Repurchase Notice pursuant to Section 311(a) of this Supplemental
Indenture has been given, or a specified percentage thereof, may be paid by the
Company with cash equal to the aggregate Fundamental Change Repurchase Price or
such percentage of the aggregate Fundamental Change Repurchase Price of such
Notes. Any cash payment owing pursuant to the preceding sentence will be made on
or before November 30, 2002 and will accrue interest from the Fundamental Change
Repurchase Date at a rate of 22 basis points above the three month London
Interbank Offered Rate in effect two Business days before the Fundamental Change
Repurchase Date through the date of payment. All Notes repurchased subsequent to
October 31, 2002, pursuant to Section 311(a) of this Supplemental Indenture,
will be paid in cash.

               (d) Payment by Issuance of Common Stock. For any Fundamental
Change repurchase occurring prior to October 31, 2002, at the option of the
Company, the Fundamental Change Repurchase Price of Notes in respect of which a
Fundamental Change Repurchase Notice pursuant to Section 311(a) of this
Supplemental Indenture has been given, or a specified percentage thereof, may be
paid by the Company by the issuance of a number of shares of Common Stock equal
to the quotient obtained by dividing (i) the amount of cash to which the



                                       37
<PAGE>   42

Holders would have been entitled had the Company elected to pay all or such
specified percentage, as the case may be, of the Fundamental Change Repurchase
Price of such Notes in cash by (ii) 0.975 times the Market Price of a share of
Common Stock, subject to the next succeeding paragraph. All Notes repurchased
subsequent to October 31, 2002, pursuant to Section 311(a) of this Supplemental
Indenture, will be paid in cash.

               The Company will not issue a fractional share of Common Stock in
payment of the Fundamental Change Repurchase Price. Instead the Company will pay
cash for the current market value of the fractional share. The current market
value of a fraction of a share shall be determined, to the nearest 1/1,000th of
a share, by multiplying the Market Price by such fraction and rounding the
product to the nearest whole cent. It is understood that if a Holder elects to
have more than one Note purchased, the number of shares of Common Stock shall be
based on the aggregate amount of Notes to be purchased.

               The Company's right to exercise its election to purchase the
Notes pursuant to Section 311 of this Supplemental Indenture through the
issuance by the Company of shares of Common Stock shall be conditioned upon:

               (i) the Company's not having given a Fundamental Change Notice of
        an election to pay entirely in cash and its timely giving of its
        Fundamental Change Notice of election to purchase all or a specified
        percentage of the Notes with Common Stock as provided herein;

               (ii) the registration of the shares of Common Stock to be issued
        in respect of the payment of the Fundamental Change Repurchase Price
        under the Securities Act or the Exchange Act, in each case if required;

               (iii) any necessary qualification or registration under
        applicable state securities laws or the availability of an exemption
        from such qualification and registration; and

               (iv) the receipt by the Trustee of an Officers' Certificate and
        an Opinion of Counsel, each stating that (A) the terms of the issuance
        of the Common Stock are in conformity with this Indenture and (B) the
        shares of Common Stock to be issued by the Company in payment of the
        Fundamental Change Repurchase Price in respect of Notes have been duly
        authorized and, when issued and delivered pursuant to the terms of this
        Indenture in payment of the Fundamental Change Repurchase Price in
        respect of the Notes, will be validly issued, fully paid and
        non-assessable and, to the best of such counsel's knowledge, free from
        preemptive rights, and, in the case of such Officers' Certificate,
        stating that conditions (i), (ii) and (iii) above and the condition set
        forth in the second succeeding sentence have been satisfied and, in the
        case of such Opinion of Counsel, stating that condition (ii) above has
        been satisfied.

               Such Officers' Certificate shall also set forth the number of
shares of Common Stock to be issued for each $1,000 Principal Amount at Maturity
of Notes and the Sale Price of a share of Common Stock on each trading day
during the period during which the Market Price is calculated. The Company may
pay the Fundamental Change Repurchase Price (or any portion thereof) in Common
Stock only if the information necessary to calculate the Market Price is



                                       38
<PAGE>   43

published in a daily newspaper of national circulation. If the foregoing
conditions are not satisfied with respect to a Holder or Holders prior to the
close of business on the Fundamental Change Repurchase Date and the Company has
elected to purchase the Notes pursuant to this Section 311 through the issuance
by the Company of shares of Common Stock, the Company shall pay the entire
Fundamental Change Repurchase Price of the Notes of such Holder or Holders in
cash.

               (e) Notice of Fundamental Change and Company's Election. Within
30 days after the occurrence of a Fundamental Change, the Company shall mail a
notice of such Fundamental Change (the "Fundamental Change Notice") by
first-class mail to the Trustee and to each Holder (and to beneficial owners as
required by applicable law), release such notice to the Reuters and Bloomberg
news services and publish a copy of such notice in The Wall Street Journal (or,
if The Wall Street Journal is not published at that time, another newspaper of
national circulation). For repurchases of Notes prior to October 31, 2002, the
Fundamental Change Notice shall disclose the Company's election to repurchase
with cash or Common Stock or any combination thereof in the manner provided
herein. The Fundamental Change Notice shall be sent to Holders as required by
applicable law. The notice shall include a form of Fundamental Change Repurchase
Notice to be completed by the Holder and shall state:

               (1) briefly, the events causing a Fundamental Change and the date
of such Fundamental Change;

               (2) the date as of which the Fundamental Change Repurchase Notice
pursuant to this Section 311 is to be given (the "Fundamental Change Notice
Date");

               (3) the Fundamental Change Repurchase Date;

               (4) the Fundamental Change Repurchase Price;

               (5) the name and address of the Paying Agent and the Conversion
Agent;

               (6) the applicable Conversion Rate and any adjustments thereto;

               (7) that Notes as to which a Fundamental Change Repurchase Notice
has been given may be converted pursuant to Article V of this Supplemental
Indenture hereof only if the applicable Fundamental Change Repurchase Notice has
been withdrawn in accordance with the terms of this Indenture;

               (8) that Notes must be surrendered to the Paying Agent for
cancellation to collect payment;

               (9) that the Fundamental Change Repurchase Price for any Note as
to which a Fundamental Change Repurchase Notice has been duly given and not
withdrawn will be paid promptly following the later of the Fundamental Change
Repurchase Date and the time of surrender of such Note as described in (8);

               (10) the procedures the Holder must follow to exercise rights
under this Section 311 and a brief description of those rights;



                                       39
<PAGE>   44

               (11) briefly, the conversion rights of the Notes;

               (12) the procedures for withdrawing a Fundamental Change
Repurchase Notice (including, without limitation, for a conditional withdrawal
pursuant to the terms of Section 311(a)(1)(D) or Section 312 of this
Supplemental Indenture);

               (13) that, unless the Company defaults in making payment of such
Fundamental Change Repurchase Price, Original Issue Discount on Notes covered by
any Fundamental Change Repurchase Notice (or interest, if the Notes have been
converted into semi-annual cash pay notes pursuant to Section 401 of this
Supplemental Indenture), if any, will cease to accrue on and after the
Fundamental Change Repurchase Date; and

               (14) the CUSIP or ISIN number of the Notes.

               In the event the Company has elected to pay the Fundamental
Change Repurchase Price (or a specified percentage thereof) with Common Stock,
the Fundamental Change Notice also shall:

               (1) state that each Holder will receive Common Stock in respect
of the specified percentage of the Fundamental Change Repurchase Price of the
Notes held by such Holder (except any cash amount to be paid in lieu of
fractional shares);

               (2) state that the total number of shares of Common Stock to be
issued to Holders will be equal to the quotient obtained by dividing (i) the
amount of cash to which the Holders would have been entitled had the Company
elected to pay all or such specified percentage, as the case may be, of the
Fundamental Change Repurchase Price of such Notes in cash by (ii) 0.975 times
the Market Price of a share of Common Stock;

               (3) set forth the method of calculating the Market Price of the
Common Stock; and

               (4) state that because the Market Price of Common Stock will be
determined prior to the Fundamental Change Repurchase Date, Holders will bear
the market risk with respect to the value of the Common Stock to be received
from the date such Market Price is determined to the Fundamental Change
Repurchase Date.

               At the Company's request, the Trustee shall give such Fundamental
Change Notice in the name of the Company and at the Company's expense; provided,
however, that, in all cases, the text of such Fundamental Change Notice shall be
prepared by the Company.

               (f) Covenants of the Company. All shares of Common Stock
delivered upon purchase of the Notes pursuant to this Supplemental Indenture
shall be newly issued shares or treasury shares, shall be duly authorized,
validly issued, fully paid and nonassessable, and shall be free from preemptive
rights and free of any lien or adverse claim.

               The Company shall use its best efforts to list or cause to have
quoted any such shares of Common Stock to be issued to purchase Notes on each
national securities exchange or over-the-counter or other domestic market on
which the Common Stock is then listed or quoted.



                                       40
<PAGE>   45

               (g) Procedure upon Purchase. The Company shall deposit cash (in
respect of a cash purchase under Section 311(c) of this Supplemental Indenture
or for fractional shares, as applicable) or shares of Common Stock, or a
combination thereof, as applicable, at the time and in the manner as provided in
Section 313 of this Supplemental Indenture, sufficient to pay the aggregate
Fundamental Change Repurchase Price of all Notes to be purchased pursuant to
this Section 311. As soon as practicable after the Fundamental Change Repurchase
Date, the Company shall deliver to each Holder entitled to receive Common Stock
through the Stock Transfer Agent, a certificate for the number of full shares of
Common Stock issuable in payment of the Fundamental Change Repurchase Price.
Prior to the Conversion Date, a Holder of a Note shall have no rights as a
shareholder with respect to shares of Common Stock into which such Note is
convertible. The Person in whose name the certificate for Common Stock is
registered shall be treated as a holder of record of shares of Common Stock on
the Business Day following the Fundamental Change Repurchase Date. Subject to
Section 311(d) of this Supplemental Indenture, no payment or adjustment will be
made for dividends on any Common Stock delivered in payment of the Fundamental
Change Repurchase Price the record date for which occurred on or prior to the
Fundamental Change Repurchase Date.

               (h) Taxes. If a Holder of a Note is paid in Common Stock, the
Company shall pay any documentary, stamp or similar issue or transfer tax due on
such issue of shares of Common Stock. Nothing herein shall preclude any income
tax withholding required by law or regulations.

SECTION 312. Effect of Purchase Notice or Fundamental Change Repurchase Notice.

               Upon receipt by a Paying Agent of the Purchase Notice or
Fundamental Change Repurchase Notice specified in Section 310(a) or Section
311(a) of this Supplemental Indenture, as applicable, the Holder of the Note in
respect of which such Purchase Notice or Fundamental Change Repurchase Notice,
as the case may be, was given shall (unless such Purchase Notice or Fundamental
Change Repurchase Notice is withdrawn as specified in the following two
paragraphs) thereafter be entitled to receive solely the Purchase Price or
Fundamental Change Repurchase Price, as the case may be, with respect to such
Note. Such Purchase Price or Fundamental Change Repurchase Price shall be paid
to such Holder, subject to receipts of funds and/or Notes by the Paying Agent,
promptly following the later of (x) the Purchase Date or the Fundamental Change
Repurchase Date, as the case may be, with respect to such Note (provided the
conditions in Section 310(a) or Section 311(a) of this Supplemental Indenture,
as applicable, have been satisfied) and (y) the time of delivery of such Note to
the Paying Agent by the Holder thereof in the manner required by Section 310(a)
or Section 311(a) of this Supplemental Indenture, as applicable. Notes in
respect of which a Purchase Notice or Fundamental Change Repurchase Notice, as
the case may be, has been given by the Holder thereof may not be converted
pursuant to Article V of this Supplemental Indenture hereof on or after the date
of the delivery of such Purchase Notice or Fundamental Change Repurchase Notice,
as the case may be, unless such Purchase Notice or Fundamental Change Repurchase
Notice, as the case may be, has first been validly withdrawn as specified in the
following two paragraphs.

               A Purchase Notice or Fundamental Change Repurchase Notice, as the
case may be, may be withdrawn by means of a written notice of withdrawal
delivered to the office of the Paying Agent in accordance with the Purchase
Notice or Fundamental Change Repurchase



                                       41
<PAGE>   46

Notice, as the case may be, at any time prior to the close of business on the
Purchase Date or the Fundamental Change Repurchase Date, as the case may be,
specifying:

               (1) the certificate number of the Note in respect of which such
notice of withdrawal is being submitted, if the Note is in certificated form,

               (2) the Principal Amount at Maturity of the Note with respect to
which such notice of withdrawal is being submitted, and

               (3) the Principal Amount at Maturity, if any, of such Note which
remains subject to the original Purchase Notice or Fundamental Change Repurchase
Notice, as the case may be, and which has been or will be delivered for purchase
or repurchase by the Company.

               A written notice of withdrawal of a Purchase Notice or
Fundamental Change Repurchase Notice may be in the form set forth in the
preceding paragraph or may be in the form of (i) a conditional withdrawal
contained in a Purchase Notice or Fundamental Change Repurchase Notice pursuant
to the terms of Section 310(a)(1)(D) or 311(a)(1)(D) of this Supplemental
Indenture or (ii) a conditional withdrawal containing the information set forth
in Section 310(a)(1)(D) or 311(a)(1)(D) of this Supplemental Indenture and the
preceding paragraph and contained in a written notice of withdrawal delivered to
the Paying Agent as set forth in the preceding paragraph.

               There shall be no purchase of any Notes pursuant to Section 310
or 311 of this Supplemental Indenture (other than through the issuance of Common
Stock in payment of the Purchase Price, including cash in lieu of fractional
shares) if there has occurred (prior to, on or after, as the case may be, the
giving, by the Holders of such Notes, of the required Purchase Notice or
Fundamental Change Repurchase Notice, as the case may be) and is continuing an
Event of Default (other than a default in the payment of the Purchase Price or
Fundamental Change Repurchase Price, as the case may be, with respect to such
Notes). The Paying Agent will promptly return to the respective Holders thereof
any Notes (x) with respect to which a Purchase Notice or Fundamental Change
Repurchase Notice, as the case may be, has been withdrawn in compliance with
this Indenture, or (y) held by it during the continuance of an Event of Default
(other than a default in the payment of the Purchase Price or Fundamental Change
Repurchase Price, as the case may be, with respect to such Notes) in which case,
upon such return, the Purchase Notice or Fundamental Change Repurchase Notice
with respect thereto shall be deemed to have been withdrawn.

SECTION 313. Deposit of Purchase Price or Fundamental Change Repurchase Price.

               Prior to 11:00 a.m. (New York City time) on the Business Day
following the Purchase Date or the Fundamental Change Repurchase Date, as the
case may be, the Company shall deposit with the Trustee or with the Paying Agent
(or, if the Company or a Subsidiary of the Company is the Paying Agent, shall
segregate and hold in trust) an amount of money (in immediately available funds
if deposited on such Business Day) sufficient to pay the cash portion of the
aggregate Purchase Price or Fundamental Change Repurchase Price, as the case may
be, of all the Notes (or portions thereof) which are to be purchased as of the
Purchase Date or Fundamental Change Repurchase Date, as the case may be, and
shall instruct the Stock



                                       42
<PAGE>   47

Transfer Agent to deliver the number of full shares of Common Stock issuable in
payment of the remaining portion of the aggregate Purchase Price or Fundamental
Change Repurchase Price, as the case may be. The Company shall promptly notify
the Trustee in writing of the amount of any deposits of cash or deliveries of
Common Stock made pursuant to this Section 313.

               If the Paying Agent holds money or securities sufficient to pay
the Purchase Price or Fundamental Change Repurchase Price, as the case may be,
of a Note on the Business Day following the Purchase Date or the Fundamental
Change Repurchase Date, as the case may be, then, immediately after the Purchase
Date or the Fundamental Change Repurchase Date, the Note will cease to be
outstanding and Original Issue Discount on such Note or, if the Notes have been
converted to semi-annual cash pay notes following the occurrence of a Tax Event
pursuant to Section 401 of this Supplemental Indenture, interest on such Note,
will cease to accrue, whether or not book-entry transfer is made or the Note is
delivered to the Paying Agent. Thereafter, all other rights of the Holder shall
terminate, other than the right to receive the Purchase Price or Fundamental
Change Purchase Price, as the case may be, upon delivery of the Note.

               Payment of the Purchase Price or Fundamental Change Repurchase
Price pursuant to Section 602(a) and 603(a) of this Supplemental Indenture, as
the case may be, by the Paying Agent will be made promptly following the later
of (1) the Purchase Date or Fundamental Change Repurchase Date, as the case may
be, or (2) the time of book-entry transfer or physical delivery of the Note.

SECTION 314. Notes Purchased or Repurchased in Part.

               Any Note which is to be purchased or repurchased only in part
shall be surrendered at the office of the Paying Agent (with, if the Company or
the Trustee so require, due endorsement by, or a written instrument of transfer
in form satisfactory to the Company and the Trustee duly executed by, the Holder
thereof or such Holder's attorney duly authorized in writing) and the Company
shall execute and the Trustee shall authenticate and deliver to the Holder of
such Note, without service charge, a new Note or Notes, of any authorized
denomination as requested by such Holder in aggregate Principal Amount at
Maturity equal to, and in exchange for, the portion of the Principal Amount at
Maturity of the Note so surrendered which is not purchased.

SECTION 315. Covenant to Comply with Securities Laws upon Purchase or Repurchase
             of Notes.

               In connection with any offer to purchase or repurchase or
purchase or repurchase of Notes under Section 310 or 311 of this Supplemental
Indenture (provided that such offer or purchase or repurchase constitutes a
"Company tender offer" for purposes of Rule 13e-4 (which term, as used herein,
includes any successor provision thereto) under the Exchange Act at the time of
such offer or purchase), the Company shall, to the extent legally applicable (i)
comply with Rule 13e-4 and Rule 14e-1 and any other tender offer rules under the
Exchange Act which may then be applicable, (ii) file the related Schedule TO (or
any successor schedule, form or report) under the Exchange Act, and (iii)
otherwise comply with all applicable Federal and state securities laws as
necessary to permit the rights and obligations under Sections 310 and 311 of
this Supplemental



                                       43
<PAGE>   48

Indenture to be exercised in the time and in the manner specified in Sections
310 and 311 of this Supplemental Indenture.

SECTION 316. Repayment to the Company.

               The Trustee and the Paying Agent shall return to the Company,
upon its written request therefor, any cash that remains unclaimed, together
with interest or dividends, if any, thereon, held by them for the payment of the
Purchase Price or Fundamental Change Repurchase Price, as the case may be;
provided, however, that to the extent that the aggregate amount of cash
deposited by the Company pursuant to Section 313 of this Supplemental Indenture
exceeds the cash portion of the aggregate Purchase Price or Fundamental Change
Repurchase Price, as the case may be, of the Notes (or portions thereof) which
the Company is obligated to purchase as of the Purchase Date or Fundamental
Change Repurchase Date, as the case may be, then on the Business Day following
the Purchase Date or Fundamental Change Repurchase Date, as the case may be, the
Trustee shall return any such excess to the Company, upon its written request
therefor.

                                   ARTICLE IV

                          SPECIAL TAX EVENT CONVERSION

SECTION 401. Optional Conversion to Semi-Annual Cash Pay Note Upon Tax Event.

               From and after (i) the date (the "Tax Event Date") of the
occurrence of a Tax Event and (ii) the date the Company exercises its option set
forth in this Section 401, whichever is later (the "Option Exercise Date"), at
the option of the Company, cash interest in lieu of future Original Issue
Discount shall accrue at the rate of ___% per annum on a restated principal
amount per $1,000 original Principal Amount at Maturity (the "Restated Principal
Amount") equal to the Issue Price plus Original Issue Discount accrued to the
Option Exercise Date and shall be payable semi-annually on __________ and
__________ of each year (each an "Interest Payment Date") to holders of record
at the close of business on __________ and __________ (each a "Regular Record
Date") immediately preceding such Interest Payment Date. Interest will be
computed on the basis of a 360-day year comprised of twelve 30-day months and
will accrue from the most recent date on which interest has been paid or, if no
interest has been paid, from the Option Exercise Date. Within 15 days of the
occurrence of a Tax Event, the Company shall deliver a written notice of such
Tax Event by facsimile and first-class mail to the Trustee and within 15 days of
its exercise of such option the Company shall deliver a written notice of the
Option Exercise Date by facsimile and first-class mail to the Trustee and by
first class mail to the Holders of the Notes. From and after the Option Exercise
Date, (i) the Company shall be obligated to pay at Maturity or upon a Redemption
Date, Purchase Date or Fundamental Change Repurchase Date, in lieu of the
Principal Amount at Maturity of a Note, the Restated Principal Amount thereof
plus accrued and unpaid interest and (ii) "Issue Price and accrued Original
Issue Discount," "Issue Price plus Original Issue Discount" or similar words, as
used herein, shall mean Restated Principal Amount plus accrued and unpaid
interest with respect to any Note. Notes authenticated and delivered after the
Option Exercise Date may, and shall if required by the Trustee, bear a notation
in a form approved by the Trustee as to the conversion of the Notes to
semi-annual cash pay notes.



                                       44
<PAGE>   49

SECTION 402. Paying Agent to Hold Money in Trust.

               Prior to 11 a.m. (New York City time) on any Interest Payment
Date, the Company shall deposit with the Paying Agent (or if a Subsidiary is
acting as Paying Agent, segregate and hold in trust for the benefit of the
Persons entitled thereto) a sum sufficient to pay interest when due. The Company
shall require each Paying Agent (other than the Trustee) to agree in writing
that the Paying Agent shall hold in trust for the benefit of Holders or the
Trustee all money held by the Paying Agent for the payment of principal or
interest on the Notes and shall notify the Trustee of any default by the Company
in making any such payment. If the Company or a Subsidiary acts as Paying Agent,
it shall segregate the money held by it as Paying Agent and hold it as a
separate trust fund. The Company at any time may require a Paying Agent to pay
all money held by it to the Trustee and to account for any funds disbursed by
the Paying Agent. Upon complying with this Section 402, the Paying Agent shall
have no further liability for the money delivered to the Trustee.

SECTION 403. 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
Holders. If the Trustee is not the Registrar, the Company shall furnish, or
cause the Registrar to furnish, to the Trustee, in writing at least five
Business Days before each Interest Payment Date (if applicable) 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
Holders.

SECTION 404. Payment of Interest; Interest Rights Preserved.

               (a) Interest on any Note that is payable, and is punctually paid
or duly provided for, on any Interest Payment Date shall be paid to the Person
in whose name that Note is registered at the close of business on the Regular
Record Date for such interest at the office or agency of the Company maintained
for such purpose. Each installment of interest on any Note shall be paid in
same-day funds by transfer to an account maintained by the Holder located inside
the United States, provided that with respect to any Holder, such Holder shall
have furnished to the Paying Agent all required wire payment instructions no
later than the related Regular Record Date, or if no such instructions have been
furnished, by check payable to such Holder. In the case of a Global Note,
interest payable on any Interest Payment Date will be paid to the Depositary,
with respect to that portion of such Global Note held for its account by Cede &
Co. for the purpose of permitting such party to credit the interest received by
it in respect of such Global Note to the accounts of the beneficial owners
thereof.

               Except as otherwise specified with respect to the Notes, any
interest on any Note that is payable, but is not punctually paid or duly
provided for, within 30 days following on any Interest Payment Date (herein
called "Defaulted Interest"), shall forthwith cease to be payable to the
registered Holder thereof on the relevant Regular Record Date by virtue of
having been such Holder, and such Defaulted Interest may be paid by the Company,
as its election in each case, as provided in clause (1) or (2) below:



                                       45
<PAGE>   50

               (1) The Company may elect to make payment of any Defaulted
Interest to the Persons in whose names the Notes are registered at the close of
business on a date (the "Special Record Date") for the payment of such Defaulted
Interest, which shall be fixed in the following manner. 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 (which shall not be less than
20 days after such notice is received by the Trustee), and at the same time the
Company shall deposit with the Trustee an amount of money equal to the aggregate
amount proposed to be paid in respect of such Defaulted Interest or shall make
arrangements satisfactory to the Trustee for such deposit on or prior to the
date of the proposed payment, such money when deposited to be held in trust for
the benefit of the Persons entitled to such Defaulted Interest as in this clause
provided. Thereupon the Trustee shall fix a Special Record Date for the payment
of such Defaulted Interest which shall be not more than 15 days and not less
than 10 days prior to the date of the proposed payment and not less than 10 days
after the receipt by the Trustee of the notice of the proposed payment. The
Trustee shall promptly notify the Company of such Special Record Date and, in
the name and at the expense of the Company, shall cause notice of the proposed
payment of such Defaulted Interest and the Special Record Date therefor to be
mailed, first-class postage prepaid, to each Holder of Notes at his address as
it appears on the list of Holders maintained pursuant to this Indenture not less
than 10 days prior to such Special Record Date. Notice of the proposed payment
of such Defaulted Interest and the Special Record Date therefor having been
mailed as aforesaid, such Defaulted Interest shall be paid to the Persons in
whose names the Notes are registered at the close of business on such Special
Record Date and shall no longer be payable pursuant to the following clause (2).

               (2) The Company may make payment of any Defaulted Interest on the
Notes in any other lawful manner not inconsistent with the requirements of any
securities exchange on which such Notes may be listed, and upon such notice as
may be required by such exchange, if, after notice given by the Company to the
Trustee of the proposed payment pursuant to this clause, such manner of payment
shall be deemed practicable by the Trustee.

               Subject to the foregoing provisions, each Note delivered under
this Indenture upon registration of transfer of or in exchange for or in lieu of
any other Note shall carry the rights to interest accrued and unpaid, and to
accrue, which were carried by such other Note.

                                    ARTICLE V

                                   CONVERSION

SECTION 501. Conversion Privilege.

               A Holder of a Note may convert such Note into Common Stock at any
time during the period stated in the Notes. The number of shares of Common Stock
issuable upon conversion of a Note per $1,000 of Principal Amount at Maturity
thereof (the "Conversion Rate") shall be that set forth in the Notes, subject to
adjustment as herein set forth. However, unless the relevant Notes have been
called for redemption, if the Sale Price on the trading day immediately
preceding the Conversion Date is (a) less than 100% of the sum of the Issue
Price plus accrued Original Issue Discount, with such sum divided by the
conversion rate (the "Accreted Conversion Price"), then the Holder electing to
exercise its conversion right will



                                       46
<PAGE>   51

receive, in lieu of Common Stock, cash in an amount equal to 95% of the product
of the conversion rate and such Sale Price or (b) greater than or equal to 100%
of the Accreted Conversion Price but less than 110% of the Accreted Conversion
Price, the holder will receive, in lieu of Common Stock, cash in an amount equal
to the sum of the Issue Price of the Note plus accrued Original Issue Discount.

               Any cash payment owing pursuant to the provision described in the
preceding sentence in respect of a conversion of Common Stock prior to July 1,
2003 will be made on or before July 1, 2003 and will accrue interest from the
Conversion Date at a rate of 22 basis points above the three month London
Interbank Offered Rate in effect two business days before the Conversion Date.

               If an Event of Default (other than a default in cash payment upon
conversion of the notes), has occurred and is continuing, the Company may not
pay cash upon conversion of any Notes (other than cash in lieu of fraction
shares).

               A Holder may convert a portion of the Principal Amount at
Maturity of a Note if the portion is $1,000 or an integral multiple of $1,000.
Provisions of this Indenture that apply to conversion of all of a Note also
apply to conversion of a portion of a Note.

               "Average Quoted Price" means the average of the Sale Prices of
the Common Stock for the shorter of:

               (i) 30 consecutive trading days ending on the last full trading
        day prior to the Time of Determination with respect to the rights,
        warrants or options or distribution in respect of which the Average
        Quoted Price is being calculated, or

               (ii) the period (x) commencing on the date next succeeding the
        first public announcement of (a) the issuance of rights, warrants or
        options or (b) the distribution, in each case, in respect of which the
        Average Quoted Price is being calculated and (y) proceeding through the
        last full trading day prior to the Time of Determination with respect to
        the rights, warrants or options or distribution in respect of which the
        Average Quoted Price is being calculated (excluding days within such
        period, if any, which are not trading days), or

               (iii) the period, if any, (x) commencing on the date next
        succeeding the Ex-Dividend Time with respect to the next preceding (a)
        issuance of rights, warrants or options or (b) distribution, in each
        case, for which an adjustment is required by the provisions of Section
        506(4), 507 or 508 of this Supplemental Indenture and (y) proceeding
        through the last full trading day prior to the Time of Determination
        with respect to the rights, warrants or options or distribution in
        respect of which the Average Quoted Price is being calculated (excluding
        days within such period, if any, which are not trading days).

               In the event that the Ex-Dividend Time (or in the case of a
subdivision, combination or reclassification, the effective date with respect
thereto), with respect to a dividend, subdivision, combination or
reclassification to which Section 506(1), (2), (3) or (5) of this Supplemental
Indenture applies, occurs during the period applicable for calculating



                                       47
<PAGE>   52

"Average Quoted Price" pursuant to the definition in the preceding sentence,
"Average Quoted Price" shall be calculated for such period in a manner
determined by the Board of Directors of the Company to reflect the impact of
such dividend, subdivision, combination or reclassification on the Sale Price of
the Common Stock during such period.

               "Time of Determination" means the time and date of the earlier of
(i) the determination of shareholders entitled to receive rights, warrants or
options or a distribution, in each case, to which Section 507 or 508 of this
Supplemental Indenture applies and (ii) the time ("Ex-Dividend Time")
immediately prior to the commencement of "ex-dividend" trading for such rights,
warrants or options or distribution on the New York Stock Exchange or such other
national or regional exchange or market on which the Common Stock is then listed
or quoted.

SECTION 502. Conversion Procedure.

               To convert a Note a Holder must satisfy the requirements set
forth in the Notes. The date on which the Holder satisfies all those
requirements is the conversion date (the "Conversion Date"). As soon as
practicable after the Conversion Date, the Company shall deliver to the Holder,
through the Conversion Agent, a certificate for the number of full shares of
Common Stock issuable upon the conversion and cash in lieu of any fractional
share determined pursuant to Section 503 of this Supplemental Indenture. Prior
to the Conversion Date, a Holder of a Note shall have no rights as a shareholder
with respect to the shares of Common Stock into which such Note is convertible.
The Person in whose name the certificate is registered shall be treated as a
shareholder of record on and after the Conversion Date; provided, however, that
no surrender of a Note on any date when the stock transfer books of the Company
shall be closed shall be effective to constitute the Person or Persons entitled
to receive the shares of Common Stock upon such conversion as the record holder
or holders of such shares of Common Stock on such date, but such surrender shall
be effective to constitute the Person or Persons entitled to receive such shares
of Common Stock as the record holder or holders thereof for all purposes at the
close of business on the next succeeding day on which such stock transfer books
are open; such conversion shall be at the Conversion Rate in effect on the date
that such Note shall have been surrendered for conversion, as if the stock
transfer books of the Company had not been closed. Upon conversion of a Note,
such Person shall no longer be a Holder of such Note and such Note shall be
cancelled and no longer outstanding.

               No payment or adjustment will be made for accrued Original Issue
Discount, unpaid interest, liquidated damages, dividends on, or other
distributions with respect to, any converted Note or Common Stock except as
provided in this Article V. On conversion of a Note, that portion of accrued
Original Issue Discount (or interest, if the Notes have been converted into
semi-annual cash pay notes pursuant to Section 401 of this Supplemental
Indenture) attributable to the period from the Issue Date (or, if the Company
has exercised the option provided for in Section 401 of this Supplemental
Indenture, the later of (x) the date of such exercise and (y) the date on which
interest was last paid) of the Note through the Conversion Date with respect to
the converted Note shall not be cancelled, extinguished or forfeited, but rather
shall be deemed to be paid in full to the Holder thereof through delivery of the
Common Stock (together with the cash payment, if any, in lieu of fractional
shares) in exchange for the Note being converted pursuant to the provisions
hereof; and the fair market value of such shares of Common Stock (together with
any such cash payment in lieu of fractional



                                       48
<PAGE>   53

shares) shall be treated as issued, to the extent thereof, first in exchange for
Original Issue Discount (or interest, if the Notes have been converted into
semi-annual cash pay notes pursuant to Section 401 of this Supplemental
Indenture) accrued through the Conversion Date, and the balance, if any, of such
fair market value of such Common Stock (and any such cash payment) shall be
treated as issued in exchange for the Issue Price of the Note being converted
pursuant to the provisions hereof. The Company will not advise Holders of the
amount of accrued Original Issue Discount at the time of conversion.

               If the Holder converts more than one Note at the same time, the
number of shares of Common Stock issuable upon the conversion shall be based on
the total Principal Amount at Maturity of the Notes converted.

               If the last day on which a Note may be converted is a Legal
Holiday, the Note may be surrendered on the next succeeding day that is not a
Legal Holiday.

               Upon surrender of a Note that is converted in part, the Company
shall execute, and the Trustee shall authenticate and deliver to the Holder, a
new Note in an authorized denomination equal in Principal Amount at Maturity to
the unconverted portion of the Note surrendered.

SECTION 503. Fractional Shares.

               The Company will not issue a fractional share of Common Stock
upon conversion of a Note. Instead, the Company will deliver cash for the
current market value of the fractional share. The current market value of a
fractional share shall be determined, to the nearest 1/1,000th of a share, by
multiplying the Sale Price on the trading day immediately preceding the
Conversion Date by the fractional amount and rounding the product to the nearest
whole cent.

SECTION 504. Taxes on Conversion.

               If a Holder converts a Note, the Company shall pay any
documentary, stamp or similar issue or transfer tax due on the issue of shares
of Common Stock upon the conversion. However, the Holder shall pay any such tax
which is due because the Holder requests the shares to be issued in a name other
than the Holder's name. The Conversion Agent may refuse to deliver the
certificates representing the Common Stock being issued in a name other than the
Holder's name until the Conversion Agent receives a sum that the Company deems
to be sufficient to pay any tax which will be due because the shares are to be
issued in a name other than the Holder's name. Nothing herein shall preclude any
tax withholding required by law or regulations.

SECTION 505. Company to Provide Stock.

               The Company shall, prior to issuance of any Notes under this
Article V, and from time to time as may be necessary, reserve out of its
authorized but unissued or treasury Common Stock a sufficient number of shares
of Common Stock to permit the conversion of the Notes.



                                       49
<PAGE>   54

               All shares of Common Stock delivered upon conversion of the Notes
shall be newly issued shares or treasury shares, shall be duly authorized and
validly issued, fully paid and nonassessable, and shall be free from preemptive
rights and free of any lien or adverse claim.

               The Company will endeavor promptly to comply with all federal and
state securities laws regulating the offer and delivery of shares of Common
Stock upon conversion of Notes, if any, including the addition of any and all
restrictive legends that are required to appear on the certificates representing
the Common Stock, and will list or cause to have quoted such shares of Common
Stock on each national securities exchange or in the over-the-counter market or
such other market on which the Common Stock is then listed or quoted.

SECTION 506. Adjustment for Change in Capital Stock.

               If, after the Issue Date of the Notes, the Company:

               (1) pays a dividend or makes a distribution on its Common Stock
in shares of its Common Stock;

               (2) subdivides its outstanding shares of Common Stock into a
greater number of shares;

               (3) combines its outstanding shares of Common Stock into a
smaller number of shares;

               (4) pays a dividend or makes a distribution on its Common Stock
in shares of its Capital Stock (other than Common Stock or rights, warrants or
options for its Capital Stock); or

               (5) issues by reclassification of its Common Stock any shares of
its Capital Stock (other than rights, warrants or options for its Capital
Stock),

then the Conversion Rate in effect immediately prior to such action shall be
adjusted so that the Holder of a Note thereafter converted may receive the
number of shares of Capital Stock of the Company which such Holder would have
owned immediately following such action if such Holder had converted the Note
immediately prior to such action.

               The adjustment shall become effective immediately after the
record date in the case of a dividend or distribution and immediately after the
effective date in the case of a subdivision, combination or reclassification.

               If after an adjustment a Holder of a Note upon conversion of such
Note may receive shares of two or more classes of Capital Stock of the Company,
the Conversion Rate shall thereafter be subject to adjustment upon the
occurrence of an action taken with respect to any such class of Capital Stock as
is contemplated by this Article V with respect to the Common Stock, on terms
comparable to those applicable to Common Stock in this Article V.



                                       50
<PAGE>   55

SECTION 507. Adjustment for Rights Issue.

               If after the Issue Date of the Notes, the Company distributes any
rights, warrants or options to all holders of its Common Stock entitling them,
for a period expiring within 60 days after the record date for such
distribution, to subscribe for or purchase shares of Common Stock at a price per
share less than the Sale Price as of the Time of Determination, the Conversion
Rate shall be adjusted, subject to the provisions of the last paragraph of this
Section 507 of this Supplemental Indenture, in accordance with the formula

                       R x (O + N)
               R' = ----------------
                    (O + (N x P) / M

               where:

               R' = the adjusted Conversion Rate.

               R = the current Conversion Rate.

               O = the number of shares of Common Stock outstanding on the
record date for the distribution to which this Section 507 of this Supplemental
Indenture is being applied.

               N = the number of additional shares of Common Stock offered
pursuant to the distribution.

               P = the offering price per share of the additional shares.

               M = the Average Quoted Price, minus, in the case of (i) a
distribution to which Section 506(4) of this Supplemental Indenture applies or
(ii) a distribution to which Section 508 of this Supplemental Indenture applies,
for which, in each case, (x) the record date shall occur on or before the record
date for the distribution to which this Section 507 of this Supplemental
Indenture applies and (y) the Ex-Dividend Time shall occur on or after the date
of the Time of Determination for the distribution to which this Section 507 of
this Supplemental Indenture applies, the fair market value (on the record date
for the distribution to which this Section 507 of this Supplemental Indenture
applies) of the

               (1) Capital Stock of the Company distributed in respect of each
share of Common Stock in such Section 506(4) distribution and

               (2) assets of the Company or debt securities or any rights,
warrants or options to purchase securities of the Company distributed in respect
of each share of Common Stock in such Section 508 distribution.

               The Board of Directors shall determine fair market values for the
purposes of this Section 507.

               The adjustment shall become effective immediately after the
record date for the determination of shareholders entitled to receive the
rights, warrants or options to which this Section 507 applies. If all of the
shares of Common Stock subject to such rights, warrants or



                                       51
<PAGE>   56

options have not been issued when such rights, warrants or options expire, then
the Conversion Rate shall promptly be readjusted to the Conversion Rate which
would then be in effect had the adjustment upon the issuance of such rights,
warrants or options been made on the basis of the actual number of shares of
Common Stock issued upon the exercise of such rights, warrants or options.

               No adjustment shall be made under this Section 507 if the
application of the formula stated above in this Section 507 would result in a
value of R' that is equal to or less than the value of R.

SECTION 508. Adjustment for Other Distributions.

               If, after the Issue Date of the Notes, the Company distributes to
all holders of its Common Stock any of its assets, or debt securities or any
rights, warrants or options to purchase securities of the Company (including
securities or cash, but excluding (x) distributions of Capital Stock referred to
in Section 506 of this Supplemental Indenture and distributions of rights,
warrants or options referred to in Section 507 of this Supplemental Indenture
and (y) cash dividends or other cash distributions that are paid out of current
or retained earnings or earnings retained in the business as shown on the books
of the Company unless such cash dividends or other cash distributions are
Extraordinary Cash Dividends) the Conversion Rate shall be adjusted, subject to
the provisions of the last paragraph of this Section 508, in accordance with the
formula:

                    R x M
               R' = -----
                    M - F

               where:

               R' = the adjusted Conversion Rate.

               R = the current Conversion Rate.

               M = the Average Quoted Price, minus, in the case of a
distribution to which Section 306(4) of this Supplemental Indenture applies, for
which (i) the record date shall occur on or before the record date for the
distribution to which this Section 508 applies and (ii) the Ex-Dividend Time
shall occur on or after the date of the Time of Determination for the
distribution to which this Section 508 applies, the fair market value (on the
record date for the distribution to which this Section 508 applies) of any
Capital Stock of the Company distributed in respect of each share of Common
Stock in such Section 506(4) distribution.

               F = the fair market value (on the record date for the
distribution to which this Section 508 applies) of the assets, securities,
rights, warrants or options to be distributed in respect of each share of Common
Stock in the distribution to which this Section 508 is being applied (including,
in the case of cash dividends or other cash distributions giving rise to an
adjustment, all such cash distributed concurrently).

               The Board of Directors shall determine fair market values for the
purposes of this Section 508.



                                       52
<PAGE>   57

               The adjustment shall become effective immediately after the
record date for the determination of shareholders entitled to receive the
distribution to which this Section 508 applies.

               For purposes of this Section 508, the term "Extraordinary Cash
Dividend" shall mean any cash dividend with respect to the Common Stock the
amount of which, together with the aggregate amount of cash dividends on the
Common Stock to be aggregated with such cash dividend in accordance with the
provisions of this paragraph, equals or exceeds the threshold percentage set
forth in item (i) below. For purposes of item (i) below, the "Measurement
Period" with respect to a cash dividend on the Common Stock shall mean the 365
consecutive day period ending on the date prior to the Ex-Dividend Time with
respect to such cash dividend, and the "Relevant Cash Dividends" with respect to
a cash dividend on the Common Stock shall mean the cash dividends on the Common
Stock with Ex-Dividend Times occurring in the Measurement Period.

        (i) If, upon the date prior to the Ex-Dividend Time with respect a cash
        dividend on the Common Stock, the aggregate amount of such cash dividend
        together with the amounts of all Relevant Cash Dividends equals or
        exceeds on a per share basis 10% of the Sale Price of the Common Stock
        on the last trading day preceding the date of declaration by the Board
        of Directors of the cash dividend with respect to which this provision
        is being applied, then such cash dividend together with all Relevant
        Cash Dividends, shall be deemed to be an Extraordinary Cash Dividend and
        for purposes of applying the formula set forth above in this Section
        508, the value of "F" shall be equal to (y) the aggregate amount of such
        cash dividend together with the amount of all Relevant Cash Dividends,
        minus (z) the aggregate amount of all Relevant Cash Dividends for which
        a prior adjustment in the Conversion Rate was previously made under this
        Section 508.

In making the determinations required by item (i) above, the amount of cash
dividends paid on a per share basis and the amount of any Relevant Cash
Dividends specified in item (i) above, shall be appropriately adjusted to
reflect the occurrence during such period of any event described in Section 506
of this Supplemental Indenture.

               In the event that, with respect to any distribution to which this
Section 508 would otherwise apply, the difference "M-F" as defined in the above
formula is less than $1.00 or "F" is equal to or greater than "M", then the
adjustment provided by this Section 508 shall not be made and in lieu thereof
the provisions of Section 514 of this Supplemental Indenture shall apply to such
distribution.

SECTION 509. When Adjustment May be Deferred.

               No adjustment in the Conversion Rate need be made unless the
adjustment would require an increase or decrease of at least 1% in the
Conversion Rate. Any adjustments that are not made shall be carried forward and
taken into account in any subsequent adjustment.

               All calculations under this Article V shall be made to the
nearest cent or to the nearest 1/1,000th of a share, as the case may be.



                                       53
<PAGE>   58

SECTION 510. When No Adjustment Required.

               No adjustment need be made for a transaction referred to in
Section 506, 507, 508 or 514 of this Supplemental Indenture if Holders are to
participate in the transaction on a basis and with notice that the Board of
Directors of the Company determines to be fair and appropriate in light of the
basis and notice on which holders of Common Stock participate in the
transaction. Such participation by Holders may include participation upon
conversion provided that an adjustment shall be made at such time as the Holders
are no longer entitled to participate.

               No adjustment need be made for rights to purchase Common Stock
pursuant to a Company plan for reinvestment of dividends or interest.

               No adjustment need be made for rights to purchase Capital Stock
pursuant to the Company's Stockholder Protection Rights Agreement, dated as of
February 4, 1999.

               No adjustment need be made unless such adjustment, together with
any other adjustments equals at least 1% of the current Conversion Rate.

               To the extent the Notes become convertible pursuant to this
Article V into cash, no adjustment need be made thereafter as to the cash.
Interest will not accrue on the cash.

SECTION 511. Notice of Adjustment.

               Whenever the Conversion Rate is adjusted, the Company shall
promptly mail to Holders by first-class mail a notice of the adjustment. The
Company shall file with the Trustee and the Conversion Agent such notice and an
Officer's Certificate briefly stating the facts requiring the adjustment and the
manner of computing it. The certificate shall be conclusive evidence that the
adjustment is correct. Neither the Trustee nor any Conversion Agent shall be
under any duty or responsibility with respect to any such certificate except to
exhibit the same to any Holder desiring inspection thereof.

SECTION 512. Voluntary Increase.

               The Company from time to time may increase the Conversion Rate by
any amount for any period of time. Whenever the Conversion Rate is increased,
the Company shall mail to Holders by first-class mail and file with the Trustee
and the Conversion Agent a notice of the increase. The Company shall mail the
notice at least 15 days before the date the increased Conversion Rate takes
effect. The notice shall state the increased Conversion Rate and the period it
will be in effect.

               A voluntary increase of the Conversion Rate does not change or
adjust the Conversion Rate otherwise in effect for purposes of Section 506, 507
or 508 of this Supplemental Indenture.



                                       54
<PAGE>   59

SECTION 513. Notice of Certain Transactions.

               If:

               (1) the Company takes any action that would require an adjustment
in the Conversion Rate pursuant to Section 506, 507 or 508 of this Supplemental
Indenture (unless no adjustment is to occur pursuant to Section 510 of this
Supplemental Indenture); or

               (2) there is a liquidation or dissolution of the Company;

then the Company shall mail to Holders by first-class mail and file with the
Trustee and the Conversion Agent a notice stating the proposed record date for a
dividend or distribution or the proposed effective date of a subdivision,
combination, reclassification, consolidation, merger, binding share exchange,
transfer, liquidation or dissolution. The Company shall file and mail the notice
at least 15 days before such date. Failure to file or mail the notice or any
defect in it shall not affect the validity of the transaction.

SECTION 514. Reorganization of Company; Special Distributions.

               If the Company is a party to a transaction subject to Section 801
of the Base Indenture (other than a sale of all or substantially all of the
assets of the Company in a transaction in which the holders of Common Stock
immediately prior to such transaction do not receive securities, cash or other
assets of the Company or any other Person) or a merger or binding share exchange
which reclassifies or changes its outstanding Common Stock, the Person obligated
to deliver securities, cash or other assets upon conversion of Notes shall enter
into a supplemental indenture. If the issuer of securities deliverable upon
conversion of Notes is an Affiliate of the Successor Company, that Company shall
join in the supplemental indenture.

               The supplemental indenture shall provide that the Holder of a
Note may convert it into the kind and amount of securities, cash or other assets
which such Holder would have received immediately after the consolidation,
merger, binding share exchange or transfer if such Holder had converted the Note
immediately before the effective date of the transaction, assuming (to the
extent applicable) that such Holder (i) was not a constituent Person or an
Affiliate of a constituent Person to such transaction; (ii) made no election
with respect thereto; and (iii) was treated alike with the plurality of
non-electing Holders. The supplemental indenture shall provide for adjustments
which shall be as nearly equivalent as may be practical to the adjustments
provided for in this Article V. The Successor Company shall mail to Holders a
notice briefly describing the supplemental indenture.

               If this Section 514 applies, neither Section 506 nor Section 507
of this Supplemental Indenture applies.

               If the Company makes a distribution to all holders of its Common
Stock of any of its assets, or debt securities or any rights, warrants or
options to purchase securities of the Company that, but for the provisions of
the last paragraph of Section 508 of this Supplemental Indenture, would
otherwise result in an adjustment in the Conversion Rate pursuant to the
provisions of Section 508 of this Supplemental Indenture, then, from and after
the record date for determining the holders of Common Stock entitled to receive
the distribution, a Holder of a Note



                                       55
<PAGE>   60

that converts such Note in accordance with the provisions of this Indenture
shall upon such conversion be entitled to receive, in addition to the shares of
Common Stock into which the Note is convertible, the kind and amount of
securities, cash or other assets comprising the distribution that such Holder
would have received if such Holder had converted the Note immediately prior to
the record date for determining the holders of Common Stock entitled to receive
the distribution.

SECTION 515. Company Determination Final.

               Any determination that the Company or the Board of Directors of
the Company must make pursuant to Section 503, 506, 507, 508, 509, 510, 514 or
517 of this Supplemental Indenture is conclusive.

SECTION 516. Trustee's Adjustment Disclaimer.

               The Trustee has no duty to determine when an adjustment under
this Article V should be made, how it should be made or what it should be. The
Trustee has no duty to determine whether a supplemental indenture under Section
514 of this Supplemental Indenture need be entered into or whether any
provisions of any supplemental indenture are correct. The Trustee shall not be
accountable for and makes no representation as to the validity or value of any
securities or assets issued upon conversion of Notes. The Trustee shall not be
responsible for the Company's failure to comply with this Article V. Each
Conversion Agent shall have the same protection under this Section 516 as the
Trustee.

SECTION 517. Simultaneous Adjustments.

               In the event that this Article V requires adjustments to the
Conversion Rate under more than one of Sections 506(4), 507 or 508, and the
record dates for the distributions giving rise to such adjustments shall occur
on the same date, then such adjustments shall be made by applying, first, the
provisions of Section 506 of this Supplemental Indenture, second, the provisions
of Section 508 of this Supplemental Indenture and, third, the provisions of
Section 507 of this Supplemental Indenture.

SECTION 518. Successive Adjustments.

               After an adjustment to the Conversion Rate under this Article V,
any subsequent event requiring an adjustment under this Article V shall cause an
adjustment to the Conversion Rate as so adjusted.

SECTION 519. Rights Issued in Respect of Common Stock Issued Upon Conversion.

               Each share of Common Stock issued upon conversion of Notes
pursuant to this Article V shall be entitled to receive the appropriate number
of common stock or preferred stock purchase rights, as the case may be (the
"Rights"), if any, and the certificates representing the Common Stock issued
upon such conversion shall bear such legends, if any, in each case as may be
provided by the terms of any shareholder rights agreement adopted by the
Company, as the same may be amended from time to time (in each case, a "Rights
Agreement"). Provided that such Rights Agreement requires that each share of
Common Stock issued upon conversion of



                                       56
<PAGE>   61

Notes at any time prior to the distribution of separate certificates
representing the Rights be entitled to receive such Rights, then,
notwithstanding anything else to the contrary in this Article V, there shall not
be any adjustment to the Conversion Rate as a result of the issuance of Rights,
the distribution of separate certificates representing the Rights, the exercise
or redemption of such Rights in accordance with any such Rights Agreement, or
the termination or invalidation of such Rights.

                                   ARTICLE VI

                             COVENANTS AND REMEDIES

SECTION 601. Maintenance of Properties.

               The Company will cause all properties used or useful in the
conduct of its business or the business of any Subsidiary to be maintained and
kept in good condition, repair and working order and supplied with all necessary
equipment and will cause to be made all necessary repairs, renewals,
replacements, betterments and improvements thereof, all as in the judgment of
the Company may be necessary so that the business carried on in connection
therewith may be properly and advantageously conducted at all times; provided,
however, that nothing in this Section 601 shall prevent the Company from
discontinuing the operation or maintenance of any of such properties if such
discontinuance is, in the judgment of the Company, desirable in the conduct of
its business or the business of any Subsidiary and not disadvantageous in any
material respect to the Holders.

SECTION 602. Payment of Taxes and Other Claims.

               The Company will pay or discharge or cause to be paid or
discharged, before the same shall become delinquent, (1) all taxes, assessments
and governmental charges levied or imposed upon the Company or any Subsidiary or
upon the income, profits or property of the Company or any Subsidiary, and (2)
all lawful claims for labor, materials and supplies which, if unpaid, might by
law become a lien upon the property of the Company or any Subsidiary; provided,
however, that the Company shall not be required to pay or discharge or cause to
be paid or discharged any such tax, assessment, charge or claim whose amount,
applicability or validity is being contested in good faith by appropriate
proceedings.

SECTION 603. Limitation on Liens.

               The Company will not, and will not permit any Restricted
Subsidiary to, create, incur, issue, assume or guarantee any indebtedness of the
Company or any Subsidiary secured by a Lien upon any Principal Property, or upon
shares of capital stock or evidences of indebtedness issued by any Restricted
Subsidiary and owned by the Company or any Restricted Subsidiary, now owned or
hereafter owned by the Company, without making effective provision to secure all
of the Notes then outstanding by such Lien, equally and ratably with any and all
other indebtedness thereby secured, so long as such indebtedness shall be so
secured.

               The foregoing restrictions shall not apply, however, to (1) Liens
on any property existing at the time of the acquisition thereof; (2) Liens on
property of a corporation existing at the time such corporation is merged into
or consolidated with the Company or a Restricted



                                       57
<PAGE>   62

Subsidiary or at the time of a sale, lease or other disposition of the
properties of such corporation (or a division thereof) as an entirety or
substantially as an entirety to the Company or a Restricted Subsidiary, provided
that such Lien as a result of such merger, consolidation, sale, lease or other
disposition is not extended to property owned by the Company or such Restricted
Subsidiary immediately prior thereto; (3) Liens on property of a corporation
existing at the time such corporation becomes a Restricted Subsidiary; (4) Liens
securing indebtedness of a Restricted Subsidiary to the Company or to another
Restricted Subsidiary; (5) Liens to secure all or part of the cost of
acquisition, construction, development or improvement of the underlying
property, or to secure indebtedness incurred to provide funds for any such
purpose, provided that the commitment of the creditor to extend the credit
secured by any such Lien shall have been obtained not later than twenty-four
months after the later of (a) the completion of the acquisition, construction,
development or improvement of such property or (b) the placing in operation of
such property or of such property as so constructed, developed or improved; (6)
Liens on any property created, assumed or otherwise brought into existence in
contemplation of the sale or other disposition of the underlying property,
whether directly or indirectly, by way of share disposition or otherwise;
provided that the Company must have disposed of such property within 180 days
from the creation of such Liens and any indebtedness secured by such Liens shall
be without recourse to the Company or any Subsidiary; (7) Liens in favor of the
United States of America or any State thereof, or any department, agency or
instrumentality or political subdivision thereof, to secure partial, progress,
advance or other payments; (8) Liens to secure indebtedness of joint ventures in
which the Company or a Restricted Subsidiary has an interest, to the extent such
Liens are on property or assets of, or equity interests in, such joint ventures;
(9) Liens on Equipment Held for Resale; and (10) any indebtedness secured by
Liens existing on the date of this Supplemental Indenture or any extension,
renewal or replacement or refunding of any Lien existing on the date of this
Supplemental Indenture or referred to in clauses (1) to (3) or (5); provided,
however, that the aggregate principal amount of indebtedness secured thereby and
not otherwise authorized by clauses (1) to (3) or (5), shall not exceed the
aggregate principal amount of indebtedness, plus any premium or fee payable in
connection with any such extension, renewal, replacement, or refunding, so
secured at the time of such extension, renewal, replacement or refunding.

               Notwithstanding the restrictions described above, the Company and
its Restricted Subsidiaries may incur, issue, assume or guarantee debt secured
by Liens without equally and ratably securing the Notes then outstanding,
provided, that at the time of such incurrence, issuance, assumption or
guarantee, after giving effect thereto and to the retirement of any indebtedness
which is concurrently being retired, the aggregate amount of all outstanding
indebtedness secured by Liens so incurred, other than any indebtedness secured
by Liens permitted as described in clauses (1) through (10) above, and together
with all outstanding Attributable Value of all sale and leaseback transactions
permitted as described in Section 604 of this Supplemental Indenture does not
exceed 15% of the Consolidated Net Tangible Assets of the Company.

SECTION 604. Limitation on Sale and Leaseback Transactions.

               Sale and leaseback transactions by the Company or any Restricted
Subsidiary involving any Principal Property are prohibited unless either (1) the
Company or its Restricted Subsidiaries would be entitled pursuant to the
provisions described in clauses (1) through (10) of



                                       58
<PAGE>   63

the second paragraph of Section 603 of this Supplemental Indenture to issue,
assume or guarantee indebtedness secured by a Lien on such Principal Property
without equally and ratably securing the Notes then outstanding or (2) the
Company or such Restricted Subsidiary shall apply, or cause to be applied to the
retirement of its secured debt within 120 days after the effective date of the
sale and leaseback transaction, an amount not less than the greater of (i) the
net proceeds (net of all legal, title and recording tax expenses, commissions
and other fees and expenses incurred and all federal, state, provincial, foreign
and local taxes required to be paid or accrued as a liability under GAAP, as a
consequence of such sale) of the sale of the Principal Property leased pursuant
to such arrangement or (ii) the fair market value of the Principal Property so
leased. This restriction will not apply to a sale and leaseback transaction
between the Company and a Restricted Subsidiary or between Restricted
Subsidiaries or involving the taking back of a lease for a period of less than
three years.

               Notwithstanding the restrictions described above, the Company or
any Restricted Subsidiary may enter into a sale and leaseback transaction
provided, that at the time of such transaction, after giving effect thereto, the
Attributable Value thereof, together with all indebtedness secured by Liens
permitted pursuant to Section 603 of this Supplemental Indenture other than all
indebtedness secured by Liens permitted as described in clauses (1) through (10)
of the second paragraph of Section 603 of this Supplemental Indenture and other
than the Attributable Value of such sale and leaseback transactions permitted by
the preceding paragraph, does not exceed 15% of Consolidated Net Tangible Assets
of the Company.

SECTION 605. Limitation on Incurrence of Indebtedness.

               The Company will not, and will not permit any Restricted
Subsidiary to, create, incur, assume or directly or indirectly enter into any
Guarantee of, or in any other manner become directly or indirectly liable for
("incur"), any Indebtedness (including Acquired Debt), except that the Company
may incur Indebtedness if, at the time of, and immediately after giving pro
forma effect to, such incurrence of Indebtedness, the Consolidated Coverage
Ratio of the Company for the most recently ended four fiscal quarters for which
financial statements are available would be at least 2.0 to 1. The foregoing
limitations will not apply to the incurrence by the Company or any Restricted
Subsidiary, as the case may be, of any Permitted Indebtedness of such Person.

               Upon an Investment Grade Rating Date, this Section 605 will cease
to be effective.

SECTION 606. Limitation on Restricted Payments.

               The Company will not, and will not permit any Restricted
Subsidiary to, directly or indirectly, make any Restricted Payment, unless at
the time of and immediately after giving effect to the proposed Restricted
Payment (with the value of any such Restricted Payment, if other than cash, to
be as determined in good faith by the Board of Directors of the Company, which
determination shall be conclusive), (i) no Default or Event of Default shall
have occurred and be continuing or would occur as a consequence thereof, (ii)
the Company could incur at least $1.00 of additional Indebtedness pursuant to
the first sentence of Section 605 of this



                                       59
<PAGE>   64

Supplemental Indenture and (iii) the aggregate amount of all Restricted Payments
made after the Issue Date shall not exceed the Restricted Payment Amount.

               The foregoing provisions will not prohibit the following actions
(collectively, "Permitted Payments"):

               (i) the payment of any dividend within 60 days after the date of
        declaration thereof, if at such declaration date such payment would have
        been permitted under the Indenture and such payment shall be deemed to
        have been paid on such date of declaration for purposes of clause (iii)
        of the preceding paragraph;

               (ii) the redemption, repurchase, retirement or other acquisition
        of any Capital Stock or any Indebtedness of the Company that is
        subordinated in right of payment to the Notes in exchange for, or out of
        the proceeds of, the substantially concurrent sale (other than to a
        Restricted Subsidiary) of Capital Stock of the Company (other than any
        Disqualified Stock);

               (iii) the defeasance, redemption, repurchase, retirement or other
        acquisition of any Indebtedness of the Company that is subordinated in
        right of payment to the Notes in exchange for, or out of the proceeds
        of, the substantially concurrent sale of Refinancing Indebtedness that
        is (x) at least as subordinated in right of payment to the Notes as the
        Indebtedness being refinanced and (y) permitted to be incurred pursuant
        to Section 605 of this Supplemental Indenture;

               (iv) the redemption, repurchase, retirement or other acquisition
        of any Indebtedness of the Company that is subordinated in right of
        payment to the Notes upon a Change of Control to the extent required by
        the agreement governing such Indebtedness but only if the Company shall
        have complied with Section 311 of this Supplemental Indenture and
        purchased all Notes tendered pursuant to the offer to repurchase all of
        the Notes required thereby, prior to purchasing or repaying such
        Indebtedness;

               (v) payments by the Company to purchase or otherwise acquire
        Capital Stock of the Company (including options, warrants or other
        rights to acquire such Capital Stock) from departing or deceased
        directors, officers or employees of the Company or its Subsidiaries,
        whether pursuant to the terms of an employee benefit plan or employment
        agreement or otherwise; provided that the aggregate amount of all such
        repurchases shall not exceed $2 million in any fiscal year; and

               (vi) the payment by the Company of dividends on the common stock
        of the Company in an amount not to exceed $50 million in any fiscal
        year;

provided that, in the case of clauses (v) and (vi), no Default or Event of
Default shall have occurred or be continuing at the time of such Permitted
Payment after giving effect thereto.

               For purposes of clause (iii) of the first paragraph of this
Section 606, Permitted Payments made pursuant to clauses (i), (v) and (vi) of
the immediately preceding paragraph shall be included (with respect to clause
(i), as of the date of declaration) as Restricted Payments made since the Issue
Date.



                                       60
<PAGE>   65

               Upon an Investment Grade Rating Date, this Section 606 will cease
to be effective.

SECTION 607. Provision of Financial Statements and Reports.

               Whether or not the Company is then subject to Section 13(a) or
15(d) of the Exchange Act, the Company will file with the Commission (unless
such filing is not permitted under the Exchange Act), so long as the Notes are
outstanding, the annual reports, quarterly reports and other periodic reports
that the Company would have been required to file with the Commission pursuant
to such Section 13(a) or 15(d) if the Company were so subject, and such
documents shall be filed with the Commission on or prior to the respective dates
(the "Required Filing Dates") by which the Company would have been required so
to file such documents if the Company were so subject. The Company will also in
any event (i) within 15 days of each Required Filing Date, (a) transmit or cause
to be transmitted by mail to all Holders of Notes, as their names and addresses
appear in the Security Register, without cost to such Holders, and (b) file with
the Trustee copies of the annual reports, quarterly reports and other periodic
reports which the Company would have been required to file with the Commission
pursuant to Section 13(a) or 15(d) of the Exchange Act if the Company were
subject to such Sections and (ii) if filing such documents by the Company with
the Commission is prohibited under the Exchange Act, promptly upon written
request and payment of the reasonable cost of duplication and delivery, supply
copies of such documents to any prospective Holder at the Company's cost.

SECTION 608. Future Note Guarantors.

               The Company will cause each Restricted Subsidiary that Guarantees
any Bank Indebtedness promptly to execute and deliver to the Trustee a
supplemental indenture substantially in the form set forth in Exhibit D to this
Supplemental Indenture pursuant to which such Restricted Subsidiary will
guarantee the Company's obligations under the Indenture and the Notes, in
accordance with and as further provided in Article VII of this Supplemental
Indenture.

SECTION 609. Additional Limitations on Consolidation, Etc.

               The Company shall not consolidate with or merge into any other
Person or convey, transfer or lease its properties and assets substantially as
an entirety to any Person, and no Person shall consolidate with or merge into
the Company or convey, transfer or lease its properties or assets substantially
as an entirety to the Company unless, in addition to the conditions of Section
801 of the Base Indenture being met: (1) if, as a result of any such
consolidation or merger or such conveyance, transfer or lease, properties or
assets of the Company would become subject to a mortgage, pledge, lien, security
interest or other encumbrance which would not be permitted by Section 603 of
this Supplemental Indenture, the Company or such successor Person, as the case
may be, shall take such steps as shall be necessary effectively to secure the
Securities equally and ratably with (or prior to) all indebtedness secured
thereby; (2) if such transaction occurs prior to an Investment Grade Rating
Date, the Company could incur at least $1.00 of additional Indebtedness pursuant
to the first sentence of Section 604 of this Supplemental Indenture, on a pro
forma basis after giving effect to such transaction; and (3) each Guarantor
shall have by supplemental indenture confirmed that its Note Guarantee will
apply to any such successor Person's obligations under this Indenture



                                       61
<PAGE>   66

and under the Notes unless such Note Guarantor shall have been released and
discharged from all of its obligations under its Note Guarantee in accordance
with this Indenture.

SECTION 610. Additional Events of Default.

               In addition to the applicable Events of Default set forth in
Section 501 of the Base Indenture, any one of the following events shall
constitute an "Event of Default" hereunder and thereunder whenever used with
respect to the Notes in this Indenture (whatever the reason for such Event of
Default and whether it shall be voluntary or involuntary or be effected by
operation of law or pursuant to any judgment, decree or order of any court or
any order, rule or regulation of any administrative or governmental body):

               (i) a default by the Company in the payment of the Principal
        Amount at Maturity (or, if the Notes have been converted to semi-annual
        cash pay notes following the occurrence of a Tax Event, the Restated
        Principal Amount), Redemption Price, Purchase Price, or Fundamental
        Change Purchase Price with respect to any Note when such amount becomes
        due and payable;

               (ii) a default by the Company in the payment of any interest
        which becomes payable after the Notes have been converted to semi-annual
        cash pay notes following the occurrence of a Tax Event, which default
        continues for 30 days;

               (iii) a default in the performance, or breach, by the Company of
        its obligations under Section 801 of the Base Indenture or Section 609
        of this Supplemental Indenture;

               (iv) a default in the performance, or breach, by the Company of
        its obligations under Article VI of this Supplemental Indenture, and
        continuance of such default or breach for a period of 30 days after
        there has been given, by registered or certified mail, to the Company by
        the Trustee or to the Company and the Trustee by the Holders of at least
        25% in aggregate principal amount at maturity of the Notes a written
        notice specifying such default or breach and requiring it to be remedied
        and stating that such notice is a "Notice of Default" hereunder, unless
        the Trustee, or the Trustee and the Holders of a principal amount of
        Securities of such series not less than the principal amount of
        Securities the Holders of which gave such notice, as the case may be,
        shall agree in writing to an extension of such period prior to its
        expiration;

               (v) a default in the performance, or breach, of any covenant of
        the Company in this Indenture (other than a covenant a default in whose
        performance or whose breach is elsewhere in this Section specifically
        dealt with or which has expressly been included in this Indenture solely
        for the benefit of series of Securities other than that series), and
        continuance of such default or breach for a period of 60 days after
        there has been given, by registered or certified mail, to the Company by
        the Trustee or to the Company and the Trustee by the Holders of at least
        25% in aggregate principal amount at maturity of the Notes a written
        notice specifying such default or breach and requiring it to be remedied
        and stating that such notice is a "Notice of Default" hereunder, unless
        the Trustee, or the Trustee and the Holders of a principal amount of
        Securities of such series not less than



                                       62
<PAGE>   67

        the principal amount of Securities the Holders of which gave such
        notice, as the case may be, shall agree in writing to an extension of
        such period prior to its expiration;

               (vi) a failure to pay when due (subject to any applicable grace
        period) the principal of, or acceleration of, any Indebtedness for money
        borrowed by the Company or by any Restricted Subsidiary having an
        aggregate principal amount outstanding of at least $50.0 million, if in
        the case of any such failure, such Indebtedness has not been discharged
        or, in the case of any such acceleration, such acceleration has not been
        rescinded or annulled, in each case within 10 days after there has been
        given, by registered or certified mail, to the Company by the Trustee or
        to the Company and the Trustee by the Holders of at least 25% in
        aggregate principal amount at maturity of the Notes a written notice
        specifying such default or breach and requiring it to be remedied and
        stating that such notice is a "Notice of Default" hereunder;

               (vii) any final and nonappealable judgment or decree for the
        payment of money in excess (net of any amount covered by insurance) of
        $50.0 million against the Company or any Significant Subsidiary if (A)
        an enforcement proceeding thereon is commenced by any creditor or (B) it
        is not discharged, waived or stayed and remains outstanding for a period
        of 60 days;

               (viii) the entry by a court having jurisdiction in the premises
        of (A) a decree or order for relief in respect of the Company or any
        Restricted Subsidiary in an involuntary case or proceeding under any
        applicable Federal or State bankruptcy, insolvency, reorganization or
        other similar law or (B) a decree or order adjudging the Company or any
        Restricted Subsidiary a bankrupt or insolvent, or approving as properly
        filed a petition seeking reorganization, arrangement, adjustment or
        composition of or in respect of the Company or any Restricted Subsidiary
        under any applicable Federal or State law, or appointing a custodian,
        receiver, liquidator, assignee, trustee, sequestrator or other similar
        official of the Company or any Restricted Subsidiary or of any
        substantial part of its respective property, or ordering the winding up
        or liquidation of its affairs, and the continuance of any such decree or
        order for relief or any such other decree or order unstayed and in
        effect for a period of 60 consecutive days;

               (ix) the commencement by the Company or any Restricted Subsidiary
        of a voluntary case or proceeding under any applicable Federal or State
        bankruptcy, insolvency, reorganization or other similar law or of any
        other case or proceeding to be adjudicated a bankrupt or insolvent, or
        the consent by it to the entry of a decree or order for relief in
        respect of the Company or any Restricted Subsidiary in an involuntary
        case or proceeding under any applicable Federal or State bankruptcy,
        insolvency, reorganization or other similar law or to the commencement
        of any bankruptcy or insolvency case or proceeding against it, or the
        filing by it of a petition or answer or consent seeking reorganization
        or relief under any applicable Federal or State law, or the consent by
        it to the filing of such petition or to the appointment of or taking
        possession by a custodian, receiver, liquidator, assignee, trustee,
        sequestrator other similar official of the Company or any Restricted
        Subsidiary or of any substantial part of its respective property, or the
        making by it of an assignment for the benefit of creditors, or the
        admission by it in writing of its inability to pay its debts generally
        as they become due, or



                                       63
<PAGE>   68

        the taking of corporate action by the Company or any Restricted
        Subsidiary in furtherance of any such action; or

               (x) any Note Guarantee ceasing to be in full force and effect or
        any Guarantor denying in writing that it has any liability under its
        Note Guarantee (other than by reason of the termination of the Indenture
        or the release of any such Note Guarantee in accordance with this
        Indenture).

SECTION 611. Acceleration of Maturity; Rescission and Annulment.

               If an Event of Default occurs and is continuing, unless the
principal of the Notes has already become due and payable, the Trustee by notice
to the Company, or the Holders of not less than 25 percent in aggregate
Principal Amount at Maturity of the Notes then outstanding by notice to the
Company and the Trustee may declare the Issue Price and accrued Original Issue
Discount to the date of declaration, and any accrued and unpaid interest through
the date of such declaration on all of the Notes to be immediately due and
payable. Upon such a declaration, such Issue Price and accrued Original Issue
Discount, and such accrued and unpaid interest, if any, shall be due and payable
immediately. If an Event of Default specified in Section 501 (5) or (6) of the
Base Indenture or Section 610 (viii) or (ix) of this Supplemental Indenture
occurs and is continuing, the Issue Price and accrued Original Issue Discount
accrued to the date of the occurrence of the bankruptcy, insolvency or
reorganization on all of the Notes shall automatically become and be immediately
due and payable without any declaration or other act on the part of the Trustee
or any Holders. The Holders of a majority in aggregate Principal Amount at
Maturity of the Notes then outstanding, on behalf of the Holders of all of the
Notes, by notice to the Company and the Trustee (and without notice to any other
Holder), may rescind an acceleration and its consequences if the rescission
would not conflict with any judgment or decree and if all existing Events of
Default have been cured or waived except nonpayment of the Issue Price and
accrued Original Issue Discount on any of the Notes that have become due solely
as a result of acceleration. No such rescission shall affect any subsequent
Default or impair any right consequent thereto.

               In case the Trustee shall have proceeded to enforce any right
under this Supplemental Indenture and such proceedings shall have been
discontinued or abandoned because of such waiver or rescission and annulment or
for any other reason or shall have been determined adversely to the Trustee,
then and in every such case the Company, the Holders of Notes, and the Trustee
shall be restored respectively to their several positions and rights hereunder
and all rights, remedies and powers of the Company, the Holders of Notes, and
the Trustee shall continue as though no such proceeding had been taken.

               If a Default or any Event of Default occurs and is continuing and
is known to the Trustee, the Trustee shall within 120 days after the occurrence
of such Default or Event of Default, mail to all Holders, as the names and
addresses of such Holders appear upon the Note register, notice of all Defaults
or Events of Default known to the Trustee, unless such Default or Event of
Default is cured or waived before the giving of such notice and provided that,
except in the case of default in the payment of the Principal Amount at
Maturity, Issue Price, accrued Original Issue Discount, Redemption Price,
Purchase Price, Fundamental Change Purchase Price, as the case may be, on any of
the Notes, the Trustee shall be protected in withholding such



                                       64
<PAGE>   69

notice if and so long as a trust committee of directors and/or officers of the
Trustee in good faith determines that the withholding of such notice is in the
interest of the Holders.

               The Holders of a majority in Principal Amount at Maturity of the
Notes then outstanding shall have the right to direct the time, method and place
of conducting any proceedings for any remedy available to the Trustee, subject
to certain limitations specified in the Indenture.

                                   ARTICLE VII

                               The Note Guarantees

SECTION 701. Unconditional Guarantee.

               The Guarantor hereby agrees to be bound by all applicable
provisions of this Supplemental Indenture as a Guarantor and to guarantee the
Company's obligations under the Indenture and the Notes on the terms and subject
to the conditions set forth below:

               (a) Each Guarantor hereby jointly and severally and fully and
unconditionally guarantees to each Holder of a Note, authenticated and delivered
by the Trustee and its successors and assigns, that: (1) the Issue Price and
Original Issue Discount accrued (or interest, if the Notes have been converted
into semi-annual cash pay notes pursuant to Section 401 of this Supplemental
Indenture) on the Notes will be duly and punctually paid in full when due,
whether at maturity, by acceleration or otherwise, and interest on the overdue
principal and (to the extent permitted by law) interest, if any, on the Notes
and all other obligations of the Company or the Guarantors to the Holders or the
Trustee hereunder and thereunder (including fees, expenses or other) and all
other Indenture Obligations will be promptly paid in full or performed, all in
accordance with the terms hereof; and (2) in case of any extension of time of
payment or renewal of any Notes or any of such other Indenture Obligations with
respect to the Notes, the same will be promptly paid in full when due in
accordance with the terms of the extension or renewal, whether at Stated
Maturity, by acceleration or otherwise. Failing payment when due of any amount
so guaranteed, or failing performance of any other obligation of the Company to
the Holders of Notes, for whatever reason, each Guarantor will be obligated to
pay or cause the payment of, or to perform or cause the performance of, the same
immediately. An Event of Default under the Indenture or the Notes shall
constitute an event of default under this Note Guarantee, and shall entitle the
Holders of Notes of such series to accelerate the obligations of the Guarantor
hereunder in the same manner and to the same extent as the obligations of the
Company.

               Each Guarantor hereby agrees that its obligations hereunder shall
be unconditional, irrespective of the validity, regularity or enforceability of
the Indenture, the Notes or the obligations of the Company or any other
Guarantor to the Holders or the Trustee hereunder or thereunder, the absence of
any action to enforce the same, any waiver or consent by any Holder of Notes
with respect to any provisions hereof or thereof, any release of any other
Guarantor, the recovery of any judgment against the Company, any action to
enforce the same, whether or not a Note Guarantee is affixed to any particular
Note, or any other circumstance which might otherwise constitute a legal or
equitable discharge or defense of a guarantor.



                                       65
<PAGE>   70

               Each Guarantor hereby waives the benefit of diligence,
presentment, demand of payment, filing of claims with a court in the event of
insolvency or bankruptcy of the Company, any right to require a proceeding first
against the Company, protest, notice and all demands whatsoever and covenants
that (except as otherwise provided in Section 703 of this Supplemental
Indenture) its Note Guarantee will not be discharged except by complete
performance of the obligations contained in the Notes, the Indenture and this
Note Guarantee. This Note Guarantee is a guarantee of payment and not of
collection. Each Guarantor further agrees that, as between it, on the one hand,
and the Holders of Notes and the Trustee, on the other hand (1) subject to this
Article VII, the maturity of the obligations guaranteed hereby may be
accelerated as and to the extent provided in the Indenture for the purposes of
this Note Guarantee, notwithstanding any stay, injunction or other prohibition
preventing such acceleration in respect of the obligations guaranteed hereby,
and (2) in the event of any acceleration of such obligations as provided in the
Indenture, such obligations (whether or not due and payable) shall forthwith
become due and payable by such Guarantor for the purpose of this Note Guarantee.
Neither the Trustee nor any other Person shall have any obligation to enforce or
exhaust any rights or remedies or to take any other steps under any security for
the Indenture Obligations or against the Company or any other Person or any
property of the Company or any other Person before the Trustee is entitled to
demand payment and performance by any or all Guarantors of their liabilities and
obligations under their respective Note Guarantees or under the Indenture.

               Until terminated in accordance with Section 703 of this
Supplemental Indenture, this Note Guarantee shall remain in full force and
effect and continue to be effective should any petition be filed by or against
the Company for liquidation or reorganization, should the Company become
insolvent or make an assignment for the benefit of creditors or should a
receiver or trustee be appointed for all or any significant part of the
Company's assets, and shall, to the fullest extent permitted by law, continue to
be effective or be reinstated, as the case may be, if at any time payment and
performance of the Notes are, pursuant to applicable law, rescinded or reduced
in amount, or must otherwise be restored or returned by any obligee on such
Notes, whether as a "voidable preference," "fraudulent transfer" or otherwise,
all as though such payment or performance had not been made. In the event that
any payment, or any part thereof, is rescinded, reduced, restored or returned,
the Notes of the relevant series shall, to the fullest extent permitted by law,
be reinstated and deemed reduced only by such amount paid and not so rescinded,
reduced, restored or returned.

               (b) Each Guarantor that makes a payment or distribution under
this Note Guarantee shall have the right to seek contribution from any
non-paying Guarantor so long as the exercise of such right does not impair the
rights of the Holders under this Note Guarantee.

               (c) Notwithstanding any of the foregoing, each Guarantor's
liability under this Note Guarantee shall be limited to the maximum amount that
would not result in this Note Guarantee constituting a fraudulent conveyance or
fraudulent transfer under applicable law.

               (d) Each Guarantor acknowledges that it will receive direct and
indirect benefits from the financing arrangements contemplated by the Indenture
and that its Note Guarantee, and the waiver set forth in Section 704 of this
Supplemental Indenture, is knowingly made in contemplation of such benefits.



                                       66
<PAGE>   71

SECTION 702. Additional Note Guarantors.

               Each Restricted Subsidiary that is required to become a Note
Guarantor pursuant to Section 608 of this Supplemental Indenture shall promptly
execute and deliver to the Trustee a supplemental indenture substantially in the
form set forth in Exhibit D to this Supplemental Indenture, evidencing its Note
Guarantee on substantially the terms set forth in this Article VII. Concurrently
therewith, the Company shall deliver to the Trustee an Opinion of Counsel in
form and substance reasonably satisfactory to the Trustee to the effect that
such supplemental indenture has been duly authorized, executed and delivered by
such Restricted Subsidiary and that, subject to the applicable bankruptcy,
insolvency, fraudulent transfer, fraudulent conveyance, reorganization,
moratorium and other laws now or hereafter in effect affecting creditors' rights
or remedies generally and the general principles of equity, such supplemental
indenture is a valid and binding agreement of such Restricted Subsidiary,
enforceable against such Restricted Subsidiary in accordance with its terms.

SECTION 703. Release of a Note Guarantee.

               (a) Any Guarantor shall be automatically and unconditionally
released and discharged from all of its obligations under its Note Guarantee,
and such Note Guarantee shall terminate, at any such time that such Guarantor is
released and discharged from all of its obligations under all of its Guarantees
in respect of Bank Indebtedness, unless such release results from payment under
such Guarantee. Upon the delivery by the Company to the Trustee of an Officers'
Certificate and, if requested by the Trustee, an Opinion of Counsel to the
effect that the transaction giving rise to such release of such Note Guarantee
was made by the Company in accordance with the provisions of the Indenture and
the Notes, the Trustee shall execute any documents reasonably required in order
to evidence such release and discharge of such Guarantor from its obligations
under and termination of its Note Guarantee.

               (b) Upon the sale, exchange or transfer to any Person not an
Affiliate of the Company of all of the Capital Stock held by the Company and its
Subsidiaries in, or all or substantially all the assets of, a Guarantor (which
sale, exchange or transfer is not prohibited by the Indenture), such Guarantor
shall be automatically and unconditionally released and discharged from all its
obligations under its Note Guarantee, and such Note Guarantee shall terminate.
Upon such occurrence, the Trustee shall execute any documents reasonably
required in order to evidence such release, discharge and termination in respect
of such Note Guarantee.

               (c) Upon the release of any Guarantor from its Note Guarantee
pursuant to the provisions of the Indenture, each other Guarantor not so
released shall remain liable for the full amount of principal of, and premium,
if any, and interest on, the Notes as and to the extent provided in this Article
VII.

               (d) Each Note Guarantee shall terminate and cease to be of
further effect upon satisfaction and discharge of the Indenture in accordance
with Section 401 of the Base Indenture.

SECTION 704. Waiver of Subrogation.

               Each Guarantor hereby irrevocably waives any claim or other
rights which it may now or hereafter acquire against the Company that arise from
the existence, payment,



                                       67
<PAGE>   72

performance or enforcement of the Company's obligations under the Notes and the
Indenture or such Guarantor's obligations under its Note Guarantee and the
Indenture, including, without limitation, any right of subrogation,
reimbursement, exoneration, indemnification, and any right to participate in any
claim or remedy of any Holder of Notes against the Company, whether or not such
claim, remedy or right arises in equity, or under contract, statute or common
law, until the Indenture is discharged and all of the Notes are discharged and
paid in full. If any amount shall be paid to any Guarantor in violation of the
preceding sentence and the Notes shall not have been paid in full, such amount
shall have been deemed to have been paid to such Guarantor for the benefit of,
and held in trust for the benefit of, the Holders of the Notes of such series,
and shall forthwith be paid to the Trustee for the benefit of such Holders to be
credited and applied upon such Notes, whether matured or unmatured, in
accordance with the terms of the Indenture.

SECTION 705. Reliance on Judicial Order or Certificate of Liquidating Agent
             Regarding Dissolution.

               Upon any payment or distribution of assets of any Guarantor
referred to in this Article VII, the Trustee, subject to the provisions of
Section 601 of the Base Indenture, and the Holders of Notes shall be entitled to
rely upon any order or decree entered by any court of competent jurisdiction in
which such insolvency, bankruptcy, receivership, liquidation, reorganization,
dissolution, winding-up or similar case or proceeding is pending, or a
certificate of the trustee in bankruptcy, receiver, liquidating trustee,
custodian, assignee for the benefit of creditors, agent or other Person making
such payment or distribution, delivered to the Trustee or to such Holders, for
the purpose of ascertaining the Persons entitled to participate in such payment
or distribution, the holders of other Indebtedness of such Guarantor, the amount
thereof or payable thereon, the amount or amounts paid or distributed thereon
and all other facts pertinent thereto or to this Article VII.

SECTION 706. Article VII Applicable to Paying Agents.

               In case at any time any Paying Agent other than the Trustee shall
have been appointed by the Company and be then acting hereunder, the term
`Trustee' as used in this Article VII shall in such case (unless the context
otherwise requires) be construed as extending to and including such Paying Agent
within its meaning as fully for all intents and purposes as if such Paying Agent
were named in this Article VII in addition to or in place of the Trustee.

SECTION 707. No Suspension of Remedies.

               Nothing contained in this Article VII shall limit the right of
the Trustee or the Holders of Notes to take any action to accelerate the
maturity of such Notes pursuant to the Indenture or to pursue any rights or
remedies hereunder or under applicable law.



                                       68
<PAGE>   73

                                  ARTICLE VIII

                                  MISCELLANEOUS

SECTION 801. Sinking Funds.

               Article XII of the Base Indenture shall have no application. The
Notes shall not have the benefit of a sinking fund.

SECTION 802. Defeasance and Covenant Defeasance.

               Article XIII of the Base Indenture shall have no application. The
Notes are not subject to any defeasance or covenant defeasance provisions.

SECTION 803. Confirmation of Indenture.

               The Indenture, as supplemented and amended by this Supplemental
Indenture and all other indentures supplemental thereto, is in all respects
ratified and confirmed, and the Indenture, this Supplemental Indenture and all
indentures supplemental thereto shall be read, taken and construed as one and
the same instrument.

SECTION 804. Counterparts.

               The parties hereto may sigh one or more copies of this
Supplemental Indenture in counterparts, all of which together shall constitute
one and the same agreement.

SECTION 805. Governing Law.

               THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY AND CONSTURED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK (WITHOUT GIVING EFFECT TO THE
CONFLICT OF LAWS PRINCIPLES THEREOF, OTHER THAN ANY MANDATING THE APPLICATION OF
SUCH LAWS.)



                                       69
<PAGE>   74

               IN WITNESS WHEREOF, the parties hereto have caused this
Supplemental Indenture to be duly executed as of the day and year first written
above.

                                             BECKMAN COULTER, INC., as issuer


                                             By:
                                                --------------------------------
                                                Name:
                                                Title:


Attest:
        ---------------------------
        Name:
        Title:



                                       70
<PAGE>   75

                                             CITIBANK, N.A., as Trustee


                                             By:
                                                --------------------------------
                                                Name:
                                                Title:


Attest:
        ---------------------------
        Name:
        Title:



                                       71
<PAGE>   76

                                            COULTER CORPORATION, as Guarantor


                                            By:
                                               ---------------------------------
                                               Name:
                                               Title:


Attest:
        ---------------------------
        Name:
        Title:


                                            HYBRITECH INCORPORATED, as Guarantor


                                            By:
                                               ---------------------------------
                                               Name:
                                               Title:


Attest:
        ---------------------------
        Name:
        Title:



                                       72
<PAGE>   77

                                    EXHIBIT A
                                  FORM OF NOTE

               FOR PURPOSES OF SECTIONS 1273 AND 1275 OF THE INTERNAL REVENUE
CODE, THE ISSUE PRICE AND AMOUNT OF ORIGINAL ISSUE DISCOUNT WITH RESPECT TO EACH
$1,000 OF PRINCIPAL AMOUNT AT MATURITY OF THIS SECURITY ARE $________ AND
$________, RESPECTIVELY, THE ISSUE DATE IS JUNE _____, 2001 AND THE YIELD TO
MATURITY IS ____%.

               THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE
INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY
OR A NOMINEE THEREOF. THIS SECURITY MAY NOT BE EXCHANGED IN WHOLE OR IN PART FOR
A SECURITY REGISTERED, AND NO TRANSFER OF THIS SECURITY IN WHOLE OR IN PART MAY
BE REGISTERED, IN THE NAME OF ANY PERSON OTHER THAN SUCH DEPOSITARY OR A NOMINEE
THEREOF, EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE.

               UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY ("DTC"), A NEW YORK CORPORATION,
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 IN SUCH
OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS 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.



                                      A-1
<PAGE>   78

                              BECKMAN COULTER, INC.
                  Zero Coupon Convertible Senior Note Due 2021

CUSIP No. -                                      $___________ Principal Amount
                                                 at Maturity
No. ____
Issue Date: June ____, 2001                      Original Issue Discount: $_____
Issue Price: $______                             (for each $1,000 Principal
(for each $1,000 Principal Amount at Maturity)   Amount at Maturity)

               Beckman Coulter, Inc., a corporation duly organized and existing
under the laws of the State of Delaware (herein called the "Company," which term
includes any successor Person under the Indenture hereinafter referred to), for
value received, hereby promises to pay to ___________ or registered assigns, the
principal sum of __________ Dollars on ___________________.

               The principal of this Note shall not bear interest except as
specified on the other side of this Note. Original Issue Discount will accrue as
specified on the other side of this Note. This Note is convertible as specified
on the other side of this Note.

               Payment of the principal of (and premium, if any) on this Note
will be made at the office or agency of the Company maintained for that purpose
in New York, New York, 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.

               Reference is hereby made to the further provisions of this Note
set forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

               Unless the certificate of authentication hereon has been executed
by the Trustee referred to on the reverse hereof by manual signature, this Note
shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.



                                      A-2
<PAGE>   79

               IN WITNESS WHEREOF, the Company has caused this instrument to be
duly executed.

               Dated as of Date of Authentication:

                                             BECKMAN COULTER, INC.


                                             By:
                                                --------------------------------
                                                Name:
                                                     ---------------------------
                                                Title:
                                                      --------------------------


               Attest:

CITIBANK, N.A., as Trustee, certifies that this is one of the Notes referred to
in the Indenture.

Dated:

By:
    -------------------------------
    Authorized Signatory



                                      A-3
<PAGE>   80

               This Note is one of a duly authorized issue of Securities of the
Company, designated as its Zero Coupon Convertible Senior Notes Due 2021,
limited in aggregate Principal Amount at Maturity to $_____________ (subject to
automatic increase by up to $__________ in the event the Underwriters exercise
the over-allotment option granted to them in the Underwriting Agreement) (herein
called the "Notes"), issued and to be issued under a Senior Indenture, dated as
of April 25, 2001 (herein called the "Base Indenture"), as supplemented by the
First Supplemental Indenture, dated as of June ___, 2001 (herein called the
"Supplemental Indenture" and, together with the Base Indenture, the
"Indenture"), among the Company, as issuer, the Guarantors, as guarantors, and
Citibank, N.A., as Trustee (herein called the "Trustee," which term includes any
successor trustee under the Indenture), and reference is hereby made to the
Indenture and for a statement of the respective rights, limitations of rights,
duties and immunities thereunder of the Company, the Trustee and the Holders of
the Notes and of the terms upon which the Notes are, and are to be,
authenticated and delivered.

               This Note is entitled to the benefits of the certain senior Note
Guarantees of the Guarantors. Reference is made to Article VII of the
Supplemental Indenture and to the Note Guarantees for terms relating to such
Note Guarantees.

               This Note shall not bear interest, except as specified herein.
Original Issue Discount (the difference between the Issue Price and the
Principal Amount at Maturity of the Note), in the period during which a Note
remains outstanding, shall accrue at ____% per annum, on a semi-annual bond
equivalent basis using a 360-day year composed of twelve 30-day months, from the
Issue Date of this Note.

               Redemption at the Option of the Company - No sinking fund is
provided for the Notes. The Notes are redeemable as a whole, or from time to
time in part, at any time at the option of the Company at a Redemption Price
equal to the Issue Price plus the accrued Original Issue Discount through the
Redemption Date, provided that the Notes are not redeemable prior to June
______, 2004.

               The table below shows Redemption Prices of a Note per $1,000
Principal Amount at Maturity on the dates shown below and at Stated Maturity,
which prices equal the Issue Price plus accrued Original Issue Discount
calculated to each such date. The Redemption Price of a Note redeemed between
such dates shall include an additional amount reflecting the additional Original
Issue Discount accrued since the next preceding date in the table.

<TABLE>
<CAPTION>
                                           ACCRUED                 REDEMPTION
                             ISSUE         ORIGINAL ISSUE          PRICE
REDEMPTION DATE              PRICE(1)      DISCOUNT AT ____%(2)    (1) + (2)
<S>                          <C>           <C>                     <C>
June ___, 2004
June ___, 2005
June ___, 2006
June ___, 2007
June ___, 2008
June ___, 2009
June ___, 2010
June ___, 2011
</TABLE>



                                      A-4
<PAGE>   81

<TABLE>
<CAPTION>
                                           ACCRUED                 REDEMPTION
                             ISSUE         ORIGINAL ISSUE          PRICE
REDEMPTION DATE              PRICE(1)      DISCOUNT AT ____%(2)    (1) + (2)
---------------
<S>                          <C>           <C>                     <C>
June ___, 2012
June ___, 2013
June ___, 2014
June ___, 2015
June ___, 2016
June ___, 2017
June ___, 2018
June ___, 2019
June ___, 2020
At stated maturity                                                 1,000.00
</TABLE>

               If converted into a semi-annual cash pay note following the
occurrence of a Tax Event pursuant to Section 401 of the Supplemental Indenture,
this Note will be redeemable at the Restated Principal Amount plus accrued and
unpaid interest from the later of the date of such conversion and the date on
which interest was last paid through the Redemption Date; but in no event will
this Note be redeemable before June ___, 2004.

               Purchase of Notes at the Option of the Holder - Subject to the
terms and conditions of the Indenture, the Company shall become obligated to
purchase, at the option of the Holder, the Notes held by such Holder on the
following Purchase Dates and at the following Purchase Prices per $1,000
Principal Amount at Maturity, upon delivery of a Purchase Notice containing the
information set forth in the Indenture, at any time from the opening of business
on the date that is 20 Business Days prior to such Purchase Date until the close
of business on such Purchase Date and upon delivery of the Notes to the Paying
Agent by the Holder as set forth in the Indenture.

<TABLE>
<CAPTION>
       --------------------------------------------
       Purchase Date           Purchase Price
       --------------------------------------------
       <S>                     <C>
       June ___, 2004
       --------------------------------------------
       June ___, 2007
       --------------------------------------------
       June ___, 2010
       --------------------------------------------
       June ___, 2013
       --------------------------------------------
       June ___, 2016
       --------------------------------------------
</TABLE>

               With the exception of the Purchase Price (equal to the Issue
Price plus accrued Original Issue Discount to the Purchase Date) paid for Notes
purchased on June ____, 2004, which shall be in cash, the Purchase Price may be
paid, at the option of the Company, in cash or by the issuance and delivery of
shares of Common Stock of the Company valued at 97.5% of the Market Price (as
defined in the Indenture), or in any combination thereof.

               If prior to a Purchase Date this Note has been converted into a
semi-annual cash pay note following the occurrence of a Tax Event pursuant to
Section 401 of the Supplemental Indenture, the Purchase Price will be equal to
the Restated Principal Amount plus accrued and unpaid interest from the date of
such conversion to the Purchase Date.



                                      A-5
<PAGE>   82

               Repurchase of Notes at the Option of the Holder Upon a
Fundamental Change - At the option of the Holder and subject to the terms and
conditions of the Indenture, the Company shall become obligated to repurchase
the Notes if a Fundamental Change occurs prior to __________, 2004, for a
Fundamental Change Repurchase Price equal to the Issue Price plus accrued
Original Issue Discount to the Fundamental Change Repurchase Date, which
Fundamental Change Repurchase Price shall be paid in cash or, for Fundamental
Change repurchases made prior to October 31, 2002, at the option of the Company,
in Common Stock of the Company valued at 97.5% of the Market Price (as defined
in the Indenture), as long as the Common Stock is then listed on a national
securities exchange or traded on the NASDAQ Stock Market, or any combination
thereof. Any cash payment for any Fundamental Change repurchase occurring prior
to October 31, 2002 will be made on or before November 30, 2002 and will accrue
interest from the Fundamental Change Repurchase Date at a rate of 22 basis
points above the three month London Interbank Offered Rate in effect two
Business days before the Fundamental Change Repurchase Date through the date of
payment. If prior to a Fundamental Change Repurchase Date the Notes have been
converted into a semi-annual cash pay note following the occurrence of a Tax
Event pursuant to Section 401 of the Supplemental Indenture, the Fundamental
Change Repurchase Price shall be equal to the Restated Principal Amount plus
accrued and unpaid interest from the later of the date of such conversion and
the date on which interest was last paid to the Fundamental Change Repurchase
Date.

               Holders have the right to withdraw any Purchase Notice or
Fundamental Change Repurchase Notice, as the case may be, by delivering to the
Paying Agent a written notice of withdrawal in accordance with the provisions of
the Indenture.

               If cash and/or securities sufficient to pay the Purchase Price,
Redemption Price or Fundamental Change Repurchase Price, as the case may be, of
all Notes (or portions thereof) to be purchased as of the Purchase Date,
Redemption Date or the Fundamental Change Repurchase Date, as the case may be,
is deposited with the Paying Agent on the Business Day following the Purchase
Date, Redemption Date or the Fundamental Change Repurchase Date, as the case may
be, Original Issue Discount (or interest, if the Notes have been converted into
semi-annual cash pay notes pursuant to Section 401 of the Supplemental
Indenture) ceases to accrue on such Notes (or portions thereof) immediately
after such Purchase Date, Redemption Date or Fundamental Change Repurchase Date,
as the case may be, whether or not such Notes are delivered to the Paying Agent,
and the Holder thereof shall have no other rights as a Holder (other than the
right to receive the Purchase Price, Redemption Date or Fundamental Change
Repurchase Price, as the case may be, upon surrender of such Note).

               If the Company elects to pay all or part of the Purchase Price or
the Fundamental Change Repurchase Price in Common Stock, the portion of accrued
Original Issue Discount (or interest, if the Notes have been converted into
semi-annual cash pay notes pursuant to Section 401 of the Supplemental
Indenture), attributable to the period from the Issue Date (or, if the Company
has exercised its option to convert the Notes into semi-annual cash pay notes
pursuant to Section 401 of the Supplemental Indenture, the later of (x) the date
of such exercise, and (y) the date on which interest was last paid) to the
Purchase Date or the Fundamental Change Repurchase Date, as the case may be,
with respect to the surrendered Note shall not be cancelled, extinguished or
forfeited, but rather shall be deemed to be paid in full to the Holder thereof
through the delivery of the Common Stock (together with a cash payment, if any,
in lieu of



                                      A-6
<PAGE>   83

fractional shares) and cash, if any, in exchange for the Note being purchased
pursuant to the terms hereof; and such cash, if any, and the fair market value
of such shares of Common Stock (together with any such cash payment in lieu of
fractional shares) shall be treated as delivered pro rata, to the extent
thereof, first in exchange for Original Issue Discount (or interest, if the
Notes have been converted into semi-annual cash pay notes pursuant to Section
401 of the Supplemental Indenture) accrued through the Purchase Date or the
Fundamental Change Repurchase Date, as the case may be, and the balance, if any,
of such cash and the fair market value of such Common Stock (and any such cash
payment) shall be treated as delivered in exchange for the Issue Price of the
Note being purchased pursuant to the provisions hereof.

               Conversion - Subject to the next three succeeding sentences, a
Holder of a Note may convert it into Common Stock of the Company at any time
before the close of business on June ____, 2021. However, unless the relevant
Notes have been called for redemption, if the Sale Price on the trading day
immediately preceding the conversion date is (a) less than 100% of the sum of
the Issue Price plus accrued Original Issue Discount, with such sum divided by
the conversion rate (the "Accreted Conversion Price"), then the Holder electing
to exercise its conversion right will receive, in lieu of Common Stock, cash in
an amount equal to 95% of the product of the conversion rate and such Sale Price
or (b) greater than or equal to 100% of the Accreted Conversion Price but less
than 110% of the Accreted Conversion Price, the holder will receive, in lieu of
Common Stock, cash in an amount equal to the sum of the Issue Price of the Note
plus accrued Original Issue Discount. If the Note is called for redemption, the
Holder may convert it at any time before the close of business on the Business
Day immediately preceding the Redemption Date, unless the Company defaults on
the payment of the Redemption Price. A Note in respect of which a Holder has
delivered a Purchase Notice or Fundamental Change Repurchase Notice exercising
the option of such Holder to require the Company to purchase such Note may be
converted only if such Purchase Notice or Fundamental Change Repurchase Notice
is withdrawn in accordance with the terms of the Indenture.

               Any cash payment owing pursuant to the provision described in the
second sentence of the preceding paragraph in respect of a conversion of Beckman
Coulter Common Stock prior to July 1, 2003 will be made on or before July 1,
2003 and will accrue interest from the Conversion Date at a rate of 22 basis
points above the three month London Interbank Offered Rate in effect two
business days before the conversion date, determined as described in the
Indenture, through the date of payment. If an Event of Default under the
Indenture (other than a default in cash payment upon conversion of the Notes),
has occurred and is continuing, we may not pay cash upon conversion of any Notes
(other than cash in lieu of fractional shares).

               The initial Conversion Rate is _______ shares of Common Stock per
$1,000 Principal Amount at Maturity, subject to adjustment in certain events
described in the Indenture. The Company will deliver cash or a check in lieu of
any fractional share of Common Stock.

               In the event the Company exercises its option pursuant to Section
401 of the Supplemental Indenture to have interest in lieu of Original Issue
Discount accrue on the Note following a Tax Event, the Holder will be entitled
on conversion to receive the same number of shares of Common Stock such Holder
would have received if the Company had not exercised such option. If the Company
exercises such option, Notes surrendered for conversion during the period from
the close of business on any Regular Record Date next preceding any Interest



                                      A-7
<PAGE>   84

Payment Date to the opening of business on such Interest Payment Date (except
Notes to be redeemed on a date within such period) must be accompanied by
payment of an amount equal to the interest thereon that the registered Holder is
to receive. Except where Notes surrendered for conversion must be accompanied by
payment as described above, no interest on converted Notes will be payable by
the Company on any Interest Payment Date subsequent to the date of conversion.

               To convert a Note, a Holder must (1) complete and manually sign
the conversion notice below (or complete and manually sign a facsimile of such
notice) and deliver such notice to the Conversion Agent, (2) surrender the Note
to the Conversion Agent for cancellation, (3) furnish appropriate endorsements
and transfer documents if required by the Conversion Agent, the Company or the
Trustee and (4) pay any transfer or similar tax, if required.

               A Holder may convert a portion of a Note if the Principal Amount
at Maturity of such portion is $1,000 or an integral multiple of $1,000. No
payment or adjustment will be made for dividends on the Common Stock except as
provided in the Indenture. On conversion of a Note, that portion of accrued
Original Issue Discount (or interest, if the Notes have been converted into
semi-annual cash pay notes pursuant to Section 401 of the Supplemental
Indenture) attributable to the period from the Issue Date (or, if the Company
has exercised the option referred to below in "Tax Event", the later of (x) the
date of such exercise and (y) the date on which interest was last paid) through
the Conversion Date with respect to the converted Note shall not be cancelled,
extinguished or forfeited, but rather shall be deemed to be paid in full to the
Holder thereof through the delivery of the Common Stock (together with the cash
payment, if any, in lieu of fractional shares) in exchange for the Note being
converted pursuant to the terms hereof; and the fair market value of such shares
of Common Stock (together with any such cash payment in lieu of fractional
shares) shall be treated as issued, to the extent thereof, first in exchange for
Original Issue Discount (or interest, if the Notes have been converted into
semi-annual cash pay notes pursuant to Section 401 of the Supplemental
Indenture) accrued through the Conversion Date, and the balance, if any, of such
fair market value of such Common Stock (and any such cash payment) shall be
treated as issued in exchange for the Issue Price of the Note being converted
pursuant to the provisions hereof.

               The Conversion Rate will be adjusted as set forth in the
Indenture for dividends or distributions on Common Stock payable in Common Stock
or other Capital Stock; subdivisions, combinations or certain reclassifications
of Common Stock; distributions to all holders of Common Stock of certain rights
to purchase Common Stock for a period expiring within 60 days at less than the
Sale Price at the Time of Determination; and certain distributions to such
holders of assets or debt securities of the Company or certain rights to
purchase securities of the Company (excluding certain cash dividends or
distributions). However, no adjustment need be made if Holders may participate
in the transaction or in certain other cases. The Company from time to time may
voluntarily increase the Conversion Rate.

               If the Company is a party to a consolidation, merger or binding
share exchange or a transfer of all or substantially all of its assets, or upon
certain distributions described in the Indenture, the right to convert a Note
into Common Stock may be changed into a right to convert it into securities,
cash or other assets of the Company or another Person.



                                      A-8
<PAGE>   85

               Tax Event -- From and after (1) the date (the "Tax Event Date")
of the occurrence of a Tax Event and (2) the date the Company exercises such
option, whichever is later (the "Option Exercise Date"), at the option of the
Company, cash interest in lieu of future Original Issue Discount shall accrue at
the rate of ___% per annum on a principal amount per Note (the "Restated
Principal Amount") equal to the Issue Price plus Original Issue Discount accrued
to the Option Exercise Date and shall be payable semi-annually on __________ and
________ of each year (each an "Interest Payment Date") to holders of record at
the close of business on ________ or _________ (each a "Regular Record Date")
immediately preceding such Interest Payment Date. Interest will be computed on
the basis of a 360-day year comprised of twelve 30-day months and will accrue
from the most recent date to which interest has been paid or, if no interest has
been paid, from the Option Exercise Date.

               Interest on any Note that is payable, and is punctually paid or
duly provided for, on any Interest Payment Date shall be paid to the Person in
whose name that Note is registered at the close of business on the Regular
Record Date for such interest at the office or agency of the Company maintained
for such purpose. Each installment of interest on any Note shall be paid in
same-day funds by transfer to an account maintained by the payee located inside
the United States, provided that with respect to any Holder, such Holder shall
have furnished to the Paying Agent all required wire payment instructions no
later than the related Regular Record Date, or if no such instructions have been
furnished, by check payable to such Holder.

               Except as otherwise specified with respect to the Notes, any
Defaulted Interest on any Note shall forthwith cease to be payable to the
registered Holder thereof on the relevant Regular Record Date by virtue of
having been such Holder, and such Defaulted Interest may be paid by the Company
as provided for in Section 404(b) of the Supplemental Indenture.

               In the event of a deposit or withdrawal of an interest in this
Note, including an exchange, transfer, repurchase or conversion of this Note in
part only, the Trustee, as custodian of the Depositary, shall make an adjustment
on its records to reflect such deposit or withdrawal in accordance with the
rules and procedures of the Depositary.

               If an Event of Default shall occur and be continuing, the Issue
Price (or, if the Notes have been converted to semi-annual cash pay notes
pursuant to Section 401 of the Supplemental Indenture, the Restated Principal
Amount) plus the Original Issue Discount (or, if the Notes have been converted
to semi-annual cash pay notes pursuant to Section 401 of the Supplemental
Indenture, accrued but unpaid interest) accrued through such date on all the
Notes may be declared due and payable in the manner and with the effect provided
in the Indenture.

               The Indenture permits, with certain exceptions as therein
provided, the amendment thereof and the modification of the rights and
obligations of the Company and the rights of the Holders of the Notes under the
Indenture at any time by the Company and the Trustee with the consent of the
Holders of not less than a majority in aggregate Principal Amount at Maturity of
the outstanding Notes. The Indenture also contains provisions permitting the
Holders of specified percentages in aggregate Principal Amount at Maturity of
the outstanding Notes, on behalf of the Holders of all the Notes, to waive
compliance by the Company with certain provisions of the Indenture and certain
past defaults under the Indenture and their consequences. Any such consent or
waiver by the Holder of this Note shall be conclusive and



                                      A-9
<PAGE>   86

binding upon such Holder and upon all future Holders of this Note and of any
Note issued upon the registration of transfer hereof or in exchange herefor or
in lieu hereof, whether or not notation of such consent or waiver is made upon
this Note.

               As provided in and subject to the provisions of the Indenture,
the Holder of this Note shall not have the right to institute any proceeding
with respect to the Indenture or for the appointment of a receiver or trustee or
for any other remedy thereunder, unless such Holder shall have previously given
the Trustee written notice of a continuing Event of Default with respect to the
Notes, the Holders of not less than 25% in Principal Amount at Maturity of the
outstanding Notes shall have made written request to the Trustee to institute
proceedings in respect of such Event of Default as Trustee and offered the
Trustee reasonable indemnity, and the Trustee shall not have received from the
Holders of a majority in Principal Amount at Maturity of outstanding Notes a
direction inconsistent with such request, and shall have failed to institute any
such proceeding, for 60 days after receipt of such notice, request and offer of
indemnity. The foregoing shall not apply to any suit instituted by the Holder of
this Note for the enforcement of any payment of said principal hereof or
interest hereon on or after the respective due dates expressed herein.

               No reference herein to the Indenture and no provision of this
Note or of the Indenture shall alter or impair the obligation of the Company,
which is absolute and unconditional, to pay the Principal Amount at Maturity,
Restated Principal Amount, Redemption Price, Purchase Price or Fundamental
Change Repurchase Price of, and interest, if any, on, this Note at the times,
place and rate, and in the coin or currency, herein prescribed.

               As provided in the Indenture and subject to certain limitations
therein set forth, the transfer of this Note is registrable in the Security
Register, upon surrender of this Note for registration of transfer at the office
or agency of the Company in The City of New York, duly endorsed by, or
accompanied by a written instrument of transfer in form satisfactory to the
Company and the Registrar duly executed by, the Holder hereof or his attorney
duly authorized in writing, and thereupon one or more new Notes, of authorized
denominations and for the same aggregate Principal Amount at Maturity, will be
issued to the designated transferee or transferees.

               The Notes are issuable only in registered form without coupons in
denominations of $1,000 Principal Amount at Maturity and any integral multiple
of $1,000 Principal Amount at Maturity above that amount. As provided in the
Indenture and subject to certain limitations therein set forth, Notes are
exchangeable for a like aggregate Principal Amount at Maturity of Notes of a
different authorized denomination, as requested by the Holder surrendering the
same.

               No service charge shall be made for any such registration of
transfer or exchange, but the Company may require payment of a sum sufficient to
cover any tax or other governmental charge payable in connection therewith.

               Prior to due presentment of this Note for registration of
transfer, the Company, the Trustee and any agent of the Company or the Trustee
may treat the Person in whose name this Note is registered as the owner hereof
for all purposes, whether or not this Note be overdue,



                                      A-10
<PAGE>   87

and neither the Company, the Trustee nor any such agent shall be affected by
notice to the contrary.

               All terms used in this Note that are defined in the Indenture
shall have the meanings assigned to them in the Indenture.




                                      A-11
<PAGE>   88

                            FORM OF CONVERSION NOTICE

               If you want to convert this Note into Common Stock of the
Company, check the box:

               [ ]

               To convert only part of this Note, state the Principal Amount at
Maturity to be converted (which must be $1,000 or an integral multiple of
$1,000):

               $__________________________________

               If you want the stock certificate made out in another person's
name, fill in the form below:


________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
            (Insert other person's social security no. or tax ID no.)

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
            (Print or type other person's name, address and zip code)

            Date:________________________              Signed:__________________

            (Sign exactly as your name appears on the other side of this Note)

            Signature Guarantee:________________________________



                                      A-12
<PAGE>   89

                                    EXHIBIT B
                             FORM OF PURCHASE NOTICE

                                                           ________________, ___

[       ], as Registrar
[address]

Re:     Purchase of $________ Principal Amount at Maturity of
        Zero Coupon Convertible Senior Notes Due 2021 (the "Notes")
        of Beckman Coulter, Inc. (the "Company")

               This is a Purchase Notice as defined in Section 310 of the First
Supplemental Indenture, dated as of June ___, 2001 (the "Supplemental
Indenture"), among the Company, Coulter Corporation, Hybritech Incorporated, and
Citibank, N.A. (the "Trustee") under the Senior Indenture dated as of April 25,
2001 between the Company and the Trustee (the "Base Indenture" and, together
with the Supplemental Indenture, the "Indenture"). Terms used but not defined
herein shall have the meanings ascribed to them in the Indenture.

               Certificate No(s). of Notes: _____________________________

               I intend to deliver the following aggregate Principal Amount at
Maturity of Notes for purchase by the Company pursuant to Section 310(a) of the
Supplemental Indenture (in multiples of $1,000):

                $_____________________________

               I hereby agree that the Notes will be purchased as of the
Purchase Date pursuant to the terms and conditions of the Notes and the
Indenture.

               In the event that the Company elects, pursuant to Section 310(b)
of the Supplemental Indenture, to pay the Purchase Price, in whole or in part,
in shares of Common Stock but such portion of the Purchase Price is ultimately
payable entirely in cash because any of the conditions to payment of the
Purchase Price in Common Stock is not satisfied prior to the close of business
on the Purchase Date, I elect:

               CHECK ONE BOX BELOW

               (1)  [ ]  to withdraw this Purchase Notice as to all of the Notes
to which this Purchase Notice relates;

               (2)  [ ]  to withdraw this Purchase Notice as to
$___________________ Principal Amount at Maturity of Notes (Certificate No(s).
____________________); or

               (3)  [ ]  to receive cash in respect of the entire Purchase Price
for all Notes (or portions thereof) to which this Purchase Notice relates.

                                             Signed:
                                                      --------------------------



                                      B-1
<PAGE>   90

                                    EXHIBIT C
                  FORM OF FUNDAMENTAL CHANGE REPURCHASE NOTICE

                                                           ________________, ___

[       ], as Registrar
[address]

Beckman Coulter, Inc.
P.O. Box 3100
Fullerton, CA 92834-3100

Re:     Purchase of $________ Principal Amount at Maturity of
        Zero Coupon Convertible Senior Notes Due 2021 (the "Notes")
        of Beckman Coulter, Inc. (the "Company")

               This is a Fundamental Change Repurchase Notice as defined in
Section 311 of the First Supplemental Indenture, dated as of June ___, 2001 (the
"Supplemental Indenture"), among the Company, Coulter Corporation, Hybritech
Incorporated, and Citibank, N.A. (the "Trustee") under the Senior Indenture
dated as of April 25, 2001 between the Company and the Trustee (the "Base
Indenture" and, together with the Supplemental Indenture, the "Indenture").
Terms used but not defined herein shall have the meanings ascribed to them in
the Indenture.

               Certificate No(s). of Notes:  _____________________________

               I intend to deliver the following aggregate Principal Amount at
Maturity of Notes for purchase by the Company pursuant to Section 311 of the
Supplemental Indenture (in multiples of $1,000):

               $________________________________

               I hereby agree that the Notes will be purchased as of the
Fundamental Change Repurchase Date pursuant to the terms and conditions of the
Notes and the Indenture.

               In the event that the Company elects, pursuant to Section 311(b)
of the Supplemental Indenture, to pay the Fundamental Change Repurchase Price,
in whole or in part, in shares of Common Stock but such portion of the
Fundamental Change Repurchase Price is ultimately payable entirely in cash
because any of the conditions to payment of the Fundamental Change Repurchase
Price in Common Stock is not satisfied prior to the close of business on the
Fundamental Change Repurchase Date, I elect:

               CHECK ONE BOX BELOW

               (1)  [ ]  to withdraw this Fundamental Change Repurchase Notice
as to all of the Notes to which this Fundamental Change Repurchase Notice
relates;



                                      C-1
<PAGE>   91

               (2)  [ ]  to withdraw this Fundamental Change Repurchase Notice
as to $___________________ Principal Amount at Maturity of Notes (Certificate
No(s). ____________________); or

               (3)  [ ]  to receive cash in respect of the entire Fundamental
Change Repurchase Price for all Notes (or portions thereof) to which this
Fundamental Change Repurchase Notice relates.

                                             Signed:
                                                      --------------------------



                                      C-2
<PAGE>   92

                                                            DRAFT - MAY 10, 2001



                                    EXHIBIT D

           FORM OF SUPPLEMENTAL INDENTURE IN RESPECT OF NOTE GUARANTEE


               This Supplemental Indenture, dated as of __________ (this
"Supplemental Indenture"), among [name of New Guarantor] (the "New Guarantor"),
Beckman Coulter, Inc. (the "Company"), each other now existing Guarantor under,
and as defined in, the Indenture referred to below, and Citibank, N.A., as
trustee under the Indenture referred to below (the "Trustee").

                              W I T N E S S E T H:

               WHEREAS, the Company and the Trustee have heretofore become
parties to a Senior Indenture, dated as of April 25, 2001 (the "Base
Indenture"), as supplemented by the First Supplemental Indenture, dated as of
June ___, 2001 (the "First Supplemental Indenture" and, together with the Base
Indenture and as amended, supplemented, waived or otherwise modified, the
"Indenture"), among the Company, as issuer, the now existing Guarantors, as
guarantors, and Citibank, N.A., as Trustee (herein called the "Trustee," which
term includes any successor trustee under the Indenture), providing for the
issuance of $_____________ aggregate principal amount of at maturity of the
Company's Zero Coupon Convertible Senior Notes Due 2021 (the "Notes");

               WHEREAS, Sections 608 and 702 of the First Supplemental Indenture
provide that under certain circumstances the Company is required to cause the
New Guarantor to execute and deliver to the Trustee a supplemental indenture
pursuant to which the New Guarantor shall guarantee the Company's obligations
under the Notes pursuant to a Note Guarantee on the terms and conditions set
forth herein and in Article VII of the First Supplemental Indenture; and

               WHEREAS, pursuant to Section 901 of the Base Indenture, the
parties hereto are authorized to execute and deliver this Supplemental Indenture
to amend the Indenture, without the consent of any Holder;

               NOW, THEREFORE, in consideration of the foregoing and for other
good and valuable consideration, the receipt of which is hereby acknowledged,
the New Guarantor, the Company, the other Guarantors and the Trustee mutually
covenant and agree for the benefit of the Holders of the Notes as follows:

               1. Defined Terms. As used in this Supplemental Indenture, terms
                  defined in the Indenture or in the preamble or recital hereto
                  are used herein as therein defined. The words "herein,"
                  "hereof" and "hereby" and other words of similar import used
                  in this Supplemental Indenture refer to this Supplemental
                  Indenture as a whole and not to any particular section hereof.

               2. Agreement to Guarantee. The New Guarantor hereby agrees,
                  jointly and severally with all other Guarantors and fully and
                  unconditionally, to guarantee the Company's obligations under
                  the Indenture and the Notes on the terms and



                                      D-1
<PAGE>   93

                  subject to the conditions set forth in Article Thirteen of the
                  Indenture and to be bound by all other applicable provisions
                  of the Indenture as a Guarantor.

               3. Termination, Release and Discharge. The New Guarantor's Note
                  Guarantee shall terminate and be of no further force or
                  effect, and the New Guarantor shall be released and discharged
                  from all obligations in respect of such Note Guarantee, as and
                  when provided in Section 703 of the First Supplemental
                  Indenture.

               4. Parties. Nothing in this Supplemental Indenture is intended or
                  shall be construed to give any Person, other than the Holders
                  and the Trustee, any legal or equitable right, remedy or claim
                  under or in respect of the New Guarantor's Note Guarantee or
                  any provision contained herein or in Article Thirteen of the
                  Indenture.

               5. Governing Law. THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED
                  BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF
                  NEW YORK (WITHOUT GIVING EFFECT TO THE CONFLICT OF LAWS
                  PRINCIPLES THEREOF, OTHER THAN ANY MANDATING THE APPLICATION
                  OF SUCH LAWS).

               6. Ratification of Indenture; Supplemental Indentures Part of
                  Indenture. Except as expressly amended hereby, the Indenture
                  is in all respects ratified and confirmed and all the terms,
                  conditions and provisions thereof shall remain in full force
                  and effect. This Supplemental Indenture shall form a part of
                  the Indenture for all purposes, and every Holder of Notes
                  heretofore or hereafter authenticated and delivered shall be
                  bound hereby. The Trustee makes no representation or warranty
                  as to the validity or sufficiency of this Supplemental
                  Indenture.

               7. Counterparts. The parties hereto may sign one or more copies
                  of this Supplemental Indenture in counterparts, all of which
                  together shall constitute one and the same agreement.

               8. Headings. The section headings herein are for convenience of
                  reference only and shall not be deemed to alter or affect the
                  meaning or interpretation of any provisions hereof.



                                      D-2
<PAGE>   94

               IN WITNESS WHEREOF, the parties hereto have caused this
Supplemental Indenture to be duly executed as of the date first above written.

                                             [NAME OF NEW GUARANTOR],


                                             By:
                                                --------------------------------
                                                Name:
                                                Title:
                                                Address:


                                             [COMPANY]

                                             By:
                                                --------------------------------
                                                Name:
                                                Title:


                                             [Add signature block for any other
                                              existing Guarantor]

                                             [TRUSTEE]

                                             By:
                                                --------------------------------
                                                Name:
                                                Title:



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