<PAGE>   1
                                                                  EXHIBIT 4.1
===============================================================================












                        DAILEY PETROLEUM SERVICES CORP.

                                      AND

                             SUBSIDIARY GUARANTORS



                                   INDENTURE



                          Dated as of August 19, 1997



                       U.S. TRUST COMPANY OF TEXAS, N.A.

                                    Trustee


                                  $115,000,000


                     9 3/4% Senior Notes due 2007, Series A

                     9 3/4% Senior Notes due 2007, Series B












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



<PAGE>   2



                             CROSS-REFERENCE TABLE
 <TABLE>
 <CAPTION>
 TRUST INDENTURE ACT SECTION                                       INDENTURE SECTION
 <S>                                                                     <C>

 310(a)(1)..........................................................    7.10
    (a)(2)..........................................................    7.10
    (a)(3)..........................................................    N.A.
    (a)(4)..........................................................    N.A.
    (a)(5)..........................................................    7.08
    (b).............................................................    7.08; 7.10
    (c).............................................................    N.A.
 311(a).............................................................    7.11
    (b).............................................................    7.11
    (c).............................................................    N.A.
 312(a).............................................................    2.05
    (b).............................................................    11.03
    (c).............................................................    11.03
 313(a).............................................................    7.06
    (b)(1)..........................................................    N.A.
    (b)(2)..........................................................    7.06
    (c).............................................................    7.06; 11.02
    (d).............................................................    7.06
 314(a).............................................................    4.02; 4.03; 11.02
    (b).............................................................    N.A.
    (c)(1)..........................................................    11.04
    (c)(2)..........................................................    11.04
    (c)(3)..........................................................    N.A.
    (d).............................................................    N.A.
    (e).............................................................    11.05
    (f).............................................................    N.A.
 315(a).............................................................    7.01(b)
    (b).............................................................    7.05; 11.02
    (c).............................................................    7.01(a)
    (d).............................................................    7.01(c)
    (e).............................................................    6.11
 316(a)(last sentence)..............................................    2.10
    (a)(1)(A).......................................................    6.05
    (a)(1)(B).......................................................    6.02; 6.04; 9.02
    (a)(2)..........................................................    N.A.
    (b).............................................................    6.07
    (c).............................................................    N.A.
 317(a)(1)..........................................................    6.08
    (a)(2)..........................................................    6.09
    (b).............................................................    2.04
 318(a).............................................................    11.01
 318(c).............................................................    11.01
</TABLE>

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


N.A. means Not Applicable.
NOTE:  This Cross-Reference table shall not, for any purpose, be deemed to be 
part of this Indenture.


<PAGE>   3



                               TABLE OF CONTENTS
                                                                          Page
<TABLE>                                                                   ----
<CAPTION>
ARTICLE ONE             DEFINITIONS AND INCORPORATION BY REFERENCE
<S>            <C>                                                        <C>
SECTION 1.01.  DEFINITIONS.................................................-2-
SECTION 1.02.  OTHER DEFINITIONS..........................................-19-
SECTION 1.03.  INCORPORATION BY REFERENCE OF TRUST INDENTURE ACT..........-19-
SECTION 1.04.  RULES OF CONSTRUCTION......................................-20-

ARTICLE TWO             THE SECURITIES

SECTION 2.01.  FORM AND DATING............................................-20-
SECTION 2.02.  EXECUTION AND AUTHENTICATION...............................-21-
SECTION 2.03.  REGISTRAR AND PAYING AGENT.................................-22-
SECTION 2.04.  PAYING AGENT TO HOLD MONEY IN TRUST........................-23-
SECTION 2.05.  HOLDER LISTS...............................................-23-
SECTION 2.06.  TRANSFER AND EXCHANGE......................................-23-
SECTION 2.07.  BOOK-ENTRY PROVISIONS FOR GLOBAL SECURITIES................-26-
SECTION 2.08.  REPLACEMENT SECURITIES.....................................-27-
SECTION 2.09.  OUTSTANDING SECURITIES.....................................-27-
SECTION 2.10.  TREASURY SECURITIES........................................-28-
SECTION 2.11.  TEMPORARY SECURITIES.......................................-28-
SECTION 2.12.  CANCELLATION...............................................-28-
SECTION 2.13.  DEFAULTED INTEREST.........................................-28-
SECTION 2.14.  PRIVATE PLACEMENT LEGEND...................................-28-

ARTICLE THREE           REDEMPTION

SECTION 3.01.  NOTICE TO TRUSTEE..........................................-29-
SECTION 3.02.  SELECTION OF SECURITIES TO BE REDEEMED.....................-29-
SECTION 3.03.  NOTICE TO HOLDERS..........................................-30-
SECTION 3.04.  EFFECT OF NOTICE OF REDEMPTION.............................-30-
SECTION 3.05.  DEPOSIT OF REDEMPTION PRICE................................-30-
SECTION 3.06.  SECURITIES REDEEMED IN PART................................-31-

ARTICLE FOUR            COVENANTS

SECTION 4.01.  PAYMENT OF SECURITIES......................................-31-
SECTION 4.02.  SEC REPORTS................................................-31-
SECTION 4.03.  COMPLIANCE CERTIFICATE.....................................-32-
SECTION 4.04.  MAINTENANCE OF OFFICE OR AGENCY............................-32-
SECTION 4.05.  CORPORATE EXISTENCE........................................-33-
SECTION 4.06.  WAIVER OF STAY, EXTENSION OR USURY LAWS....................-33-
SECTION 4.07.  PAYMENT OF TAXES AND OTHER CLAIMS..........................-33-
SECTION 4.08.  MAINTENANCE OF PROPERTIES AND INSURANCE....................-33-
SECTION 4.09.  LIMITATION ON INCURRENCE OF ADDITIONAL INDEBTEDNESS........-34-
SECTION 4.10.  LIMITATION ON SUBORDINATED INDEBTEDNESS....................-35-
</TABLE>

                                    -i-

<PAGE>   4


<TABLE>
<S>            <C>                                                        <C>
SECTION 4.11.  LIMITATION ON RESTRICTED PAYMENTS..........................-35-
SECTION 4.12.  LIMITATION ON ASSETS SALES.................................-36-
SECTION 4.13.  LIMITATION ON LIENS SECURING INDEBTEDNESS..................-39-
SECTION 4.14.  LIMITATION ON PAYMENT RESTRICTIONS AFFECTING SUBSIDIARIES..-39-
SECTION 4.15.  LIMITATION ON TRANSACTIONS WITH RELATED PERSONS............-40-
SECTION 4.16.  LIMITATION ON CONDUCT OF BUSINESS..........................-40-
SECTION 4.17.  CHANGE OF CONTROL..........................................-40-
SECTION 4.18.  SALE-AND-LEASEBACK TRANSACTIONS............................-42-
SECTION 4.19.  ISSUANCES AND SALES OF CAPITAL STOCK OF WHOLLY OWNED 
               SUBSIDIARIES ..............................................-42-
SECTION 4.20.  REGISTRATION RIGHTS AGREEMENT..............................-43-
SECTION 4.21.  QUALIFICATION OF INDENTURE.................................-43-

ARTICLE FIVE            SUCCESSOR CORPORATION

SECTION 5.01.  WHEN COMPANY MAY MERGE, ETC................................-43-
SECTION 5.02.  SUCCESSOR CORPORATION SUBSTITUTED..........................-44-

ARTICLE SIX             DEFAULTS AND REMEDIES

SECTION 6.01.  EVENTS OF DEFAULT..........................................-44-
SECTION 6.02.  ACCELERATION...............................................-45-
SECTION 6.03.  OTHER REMEDIES.............................................-46-
SECTION 6.04.  WAIVER OF PAST DEFAULTS....................................-46-
SECTION 6.05.  CONTROL BY MAJORITY........................................-46-
SECTION 6.06.  LIMITATION ON REMEDIES.....................................-47-
SECTION 6.07.  RIGHTS OF HOLDERS TO RECEIVE PAYMENT.......................-47-
SECTION 6.08.  COLLECTION SUIT BY TRUSTEE.................................-47-
SECTION 6.09.  TRUSTEE MAY FILE PROOFS OF CLAIM...........................-48-
SECTION 6.10.  PRIORITIES.................................................-48-
SECTION 6.11.  UNDERTAKING FOR COSTS......................................-48-

ARTICLE SEVEN           TRUSTEE

SECTION 7.01.  DUTIES OF TRUSTEE..........................................-48-
SECTION 7.02.  RIGHTS OF TRUSTEE..........................................-49-
SECTION 7.03.  INDIVIDUAL RIGHTS OF TRUSTEE...............................-50-
SECTION 7.04.  TRUSTEE'S DISCLAIMER.......................................-50-
SECTION 7.05.  NOTICE OF DEFAULTS.........................................-50-
SECTION 7.06.  REPORTS BY TRUSTEE TO HOLDERS..............................-51-
SECTION 7.07.  COMPENSATION AND INDEMNITY.................................-51-
SECTION 7.08.  REPLACEMENT OF TRUSTEE.....................................-52-
SECTION 7.09.  SUCCESSOR TRUSTEE BY MERGER, ETC...........................-52-
SECTION 7.10.  ELIGIBILITY; DISQUALIFICATION..............................-53-
SECTION 7.11.  PREFERENTIAL COLLECTION OF CLAIMS AGAINST COMPANY..........-53-
</TABLE>


                                     -ii-

<PAGE>   5


<TABLE>
<S>            <C>                                                       <C>
ARTICLE EIGHT           DISCHARGE OF INDENTURE

SECTION 8.01.  TERMINATION OF COMPANY'S OBLIGATIONS.......................-53-
SECTION 8.02.  APPLICATION OF TRUST MONEY.................................-54-
SECTION 8.03.  REPAYMENT TO COMPANY.......................................-55-
SECTION 8.04.  REINSTATEMENT..............................................-55-
SECTION 8.05.  SURVIVAL OF CERTAIN OBLIGATIONS............................-55-

ARTICLE NINE            AMENDMENTS, SUPPLEMENTS AND WAIVERS

SECTION 9.01.  WITHOUT CONSENT OF HOLDERS.................................-56-
SECTION 9.02.  WITH CONSENT OF HOLDERS....................................-56-
SECTION 9.03.  COMPLIANCE WITH TRUST INDENTURE ACT........................-57-
SECTION 9.04.  REVOCATION AND EFFECT OF CONSENTS..........................-57-
SECTION 9.05.  NOTATION ON OR EXCHANGE OF SECURITIES......................-57-
SECTION 9.06.  TRUSTEE PROTECTED..........................................-58-

ARTICLE TEN             SUBSIDIARY GUARANTEES

SECTION 10.01. UNCONDITIONAL GUARANTEE....................................-58-
SECTION 10.02. SUBSIDIARY GUARANTORS MAY CONSOLIDATE, ETC., ON CERTAIN
               TERMS......................................................-59-
SECTION 10.03. RELEASE OF A SUBSIDIARY GUARANTOR..........................-60-
SECTION 10.04. LIMITATION OF SUBSIDIARY GUARANTOR'S LIABILITY.............-60-
SECTION 10.05. CONTRIBUTION...............................................-61-
SECTION 10.06. EXECUTION AND DELIVERY OF SUBSIDIARY GUARANTEE.............-61-
SECTION 10.07. SEVERABILITY...............................................-61-

ARTICLE ELEVEN          MISCELLANEOUS

SECTION 11.01. TRUST INDENTURE ACT CONTROLS...............................-62-
SECTION 11.02. NOTICES....................................................-62-
SECTION 11.03. COMMUNICATION BY HOLDERS WITH OTHER HOLDERS................-63-
SECTION 11.04. CERTIFICATE AND OPINION AS TO CONDITIONS PRECEDENT.........-63-
SECTION 11.05. STATEMENTS REQUIRED IN CERTIFICATE OR OPINION..............-64-
SECTION 11.06. RULES BY TRUSTEE AND AGENTS................................-64-
SECTION 11.07. LEGAL HOLIDAYS.............................................-64-
SECTION 11.08. GOVERNING LAW..............................................-64-
SECTION 11.09. NO ADVERSE INTERPRETATION OF OTHER AGREEMENTS..............-65-
SECTION 11.10. NO RECOURSE AGAINST OTHERS.................................-65-
SECTION 11.11. SUCCESSORS.................................................-65-
SECTION 11.12. DUPLICATE ORIGINALS........................................-65-
SECTION 11.13. SEVERABILITY...............................................-65-
SECTION 11.14. COUNTERPART................................................-65-

SIGNATURES
</TABLE>


                                   -iii-

<PAGE>   6


         INDENTURE, dated as of August 19, 1997, is among DAILEY PETROLEUM
SERVICES CORP., a Delaware corporation (the "Company"), the SUBSIDIARY
GUARANTORS (as defined hereinafter) and U.S. TRUST COMPANY OF TEXAS, N.A., as
trustee (in such capacity, the "Trustee").

                            RECITALS OF THE COMPANY

         The Company has duly authorized the creation of an issue of 9 3/4%
Senior Notes due 2007, Series A and an issue of 9 3/4% Senior Notes due 2007,
Series B (such two issues, as amended or supplemented from time to time in
accordance with the terms hereof, being herein collectively called the
"Securities"), of the tenor and in the aggregate principal amount hereinafter
set forth, and to provide therefor the Company has duly authorized the
execution and delivery of this Indenture.

         The 9 3/4% Senior Notes due 2007, Series A are to be issued and sold
in transactions exempt from registration under the Securities Act, pursuant to
the Purchase Agreement, and the 9 3/4% Senior Notes due 2007, Series B are to
be issued in exchange for the 9 3/4% Senior Notes due 2007, Series A, pursuant
to the Registration Rights Agreement.

         The Company owns, directly or indirectly, all of the outstanding
Voting Stock of each initial Subsidiary Guarantor, and each initial Subsidiary
Guarantor is engaged in businesses related to the businesses of the Company and
the other Subsidiary Guarantors. Each initial Subsidiary Guarantor will derive
direct and indirect benefit from the issuance of the Securities; accordingly,
each initial Subsidiary Guarantor has authorized its guarantee of the Company's
obligations under this Indenture and the Securities, and to provide therefor
the initial Subsidiary Guarantors have duly authorized the execution and
delivery of this Indenture.

         All things necessary have been done on the part of the Company and the
initial Subsidiary Guarantors to make the Securities, when issued against
consideration received and executed by the Company and authenticated and
delivered by the Trustee as herein provided, the valid obligations of the
Company, to make the Subsidiary Guarantees, when the notations thereof on the
Securities are executed by the initial Subsidiary Guarantors, the valid
obligation of the initial Subsidiary Guarantors and to make this Indenture a
valid agreement of the Company, the initial Subsidiary Guarantors and the
Trustee, in accordance with their respective terms.

         NOW, THEREFORE, THIS INDENTURE WITNESSETH:

         For and in consideration of the premises and the purchase of the
Securities (together with the related Subsidiary Guarantees) by the Holders
thereof, it is mutually covenanted and agreed, for the equal and proportionate
benefit of all Holders of the Securities (together with the related Subsidiary
Guarantees), without preference of one series of Securities over the other, as
follows:



                                      -1-

<PAGE>   7

                                  ARTICLE ONE

                   DEFINITIONS AND INCORPORATION BY REFERENCE

SECTION 1.01.     DEFINITIONS.

         "Additional Interest" shall have the meaning ascribed to that term in
Section 4(a) of the Registration Rights Agreement.

         "Adjusted Net Assets" of a Subsidiary Guarantor at any date shall mean
the lesser of the amount by which (i) the fair value of the property of such
Subsidiary Guarantor exceeds the total amount of liabilities, including,
without limitation, contingent liabilities (after giving effect to all other
fixed and contingent liabilities incurred or assumed on such date), but
excluding liabilities under the Subsidiary Guarantee, of such Subsidiary
Guarantor at such date and (ii) the present fair saleable value of the assets
of such Subsidiary Guarantor at such date exceeds the amount that will be
required to pay the probable liability of such Subsidiary Guarantor on its
debts (after giving effect to all other fixed and contingent liabilities
incurred or assumed on such date and after giving effect to any collection from
any Subsidiary of such Subsidiary Guarantor in respect of the obligations of
such Subsidiary under the Subsidiary Guarantee), excluding debt in respect of
the Subsidiary Guarantee, as they become absolute and matured.

         "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 specified Person means the power to
direct the management and policies of such Person directly or indirectly,
whether through the ownership of Voting Stock, by contract or otherwise; and
the terms "controlling" and "controlled" have meanings correlative to the
foregoing.

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

         "Asset" means each of the assets that are owned by the Company or a
Subsidiary on the Issue Date or that are acquired by the Company or a
Subsidiary after the Issue Date.

         "Asset Sale" means any sale, issuance, conveyance, transfer, lease, 
exchange or other disposition to any Person (including, without limitation, by
means of a sale-and-leaseback transaction or a merger of consolidation)
(collectively, for purposes of this definition, a "transfer"), directly or
indirectly, in one or a series of related transactions, of (i) any Capital Stock
of any Subsidiary held by the Company or any other Subsidiary, (ii) all or
substantially all of the properties and assets of any division or line of
business of the Company or any of its Subsidiaries or (iii) any other properties
or assets of the Company or any of its Subsidiaries other than transfers of
cash, Cash Equivalents, accounts receivable or properties or assets in the
ordinary course of business; provided that the sale, lease, conveyance or other
disposition of all or substantially all of the properties or assets of the
Company and its Subsidiaries, taken as a whole, will be governed by the
provisions of Section 4.17 and/or the provisions of Article 5 and not by the
provisions of Section 4.12. For the purposes of this definition, the term "Asset
Sale" also shall not include any of the following: (a) any transfer of
properties or assets to an Unrestricted Subsidiary, if such transfer is not
prohibited under Section 4.11; (b) any transfer of properties or assets by the
Company to a Subsidiary or by a Subsidiary to the Company or a Subsidiary (in
the case of a transfer to a Subsidiary that is not a Wholly Owned Subsidiary,
dispositions shall be excluded pursuant to this clause (b) only to the extent of
the Company's interest in such Subsidiary after giving effect to such transfer);
(c) sales of damaged, worn-out or obsolete equipment or assets that, in the
Company's


                                      -2-
<PAGE>   8
reasonable judgment, are either (1) no longer used or (2) no longer useful in
the business of the Company or its Subsidiaries; (d) any lease of any property
entered into in the ordinary course of business and with respect to which the
Company or any Subsidiary is the lessor, except any such lease that provides
for the acquisition of such property by the lessee during or at the end of the
term thereof for an amount that is less than the fair market value thereof at
the time the right to acquire such property is granted; or (e) any transfer
that but for this clause (e) would be an Asset Sale, if (1) the Company elects
to designate such transfers as not constituting Asset Sales and (2) after
giving effect to such transfers, the aggregate fair market value of the
properties or assets transferred in such transaction or any such series of
related transactions so designated by the Company does not exceed $5.0 million.

         "Attributable Indebtedness" in respect of a sale-and-leaseback
transaction means, at the time of determination, the present value (discounted
at the rate of interest implicit in such transaction, determined in accordance
with GAAP) of the obligation of the lessee for net rental payments during the
remaining term of the lease included in such sale-and-leaseback transaction
(including any period for which such lease has been extended or may, at the
option of the lessor, be extended). As used in the preceding sentence, the "net
rental payments" under any lease for any such period shall mean the sum of
rental and other payments required to be paid with respect to such period by
the lessee thereunder, excluding any amounts required to be paid by such lessee
on account of maintenance and repairs, insurance, taxes, assessments, water
rates or similar charges. In the case of any lease that is terminable by the
lessee upon payment of penalty, such net rental payment shall also include the
amount of such penalty, but no rent shall be considered as required to be paid
under such lease subsequent to the first date upon which it may be so
terminated.

         "Average Life" means, as of the date of determination, with respect to
any Indebtedness, the quotient obtained by dividing (i) the sum of the products
of (a) the number of years from such date to the date of each successive
scheduled principal payment of such Indebtedness multiplied by (b) the amount
of such principal payment by (ii) the sum of all such principal payments.

         "Board of Directors" means, with respect to any Person, the board of
directors of such Person or any committee of the board of directors of such
Person duly authorized to act on behalf of the board of directors of such
Person.

         "Board Resolution" means, with respect to any Person, a copy of a
resolution certified by the Secretary or an Assistant Secretary of such Person
to have been duly adopted by the Board of Directors of such Person and to be in
full force and effect on the date of such certification, and delivered to the
Trustee.

         "Business Day" means any day which is not a Legal Holiday.

         "Capital Stock" means, with respect to any Person, any and all shares,
interests, participations or other equivalents (however designated) of
corporate stock and any and all warrants, options and rights with respect
thereto, including each class of common stock and preferred stock of such
Person.

         "Capitalized Lease Obligation" means the discounted present value of
the rental obligations of any Person under any lease of Property, which in
accordance with GAAP, is required to be capitalized on the balance sheet of
such Person.

         "Cash Equivalents" means (a) the following kinds of investments if, in
the case of instruments referred to in clauses (i) through (iv) below, on the
date of purchase or other acquisition of any such 



                                      -3-

<PAGE>   9
instrument by the Company or any Subsidiary, the remaining term to maturity is
not more than one year: (i) readily marketable obligations issued or
unconditionally guaranteed as to principal and interest by the United States or
by any agency or authority controlled or supervised by and acting as an
instrumentality of the United States; (ii) repurchase obligations for
instruments of the type described in clause (i) for which delivery of the
instrument is made against payment; (iii) obligations (including, but not
limited to, demand or time deposits, bankers' acceptances and certificates of
deposit) issued by a depository institution or trust company incorporated or
doing business under the laws of the United States, any State thereof or the
District of Columbia or a branch or subsidiary of any such depository
institution or trust company operating outside the United States, provided that
such depository institution or trust company has, at the time of the Company's
or such Subsidiary's investment therein or contractual commitment providing for
such investment, capital, surplus or undivided profits (as of the date of such
institution's most recently published financial statements), in excess of
$100,000,000; and (iv) commercial paper issued by any Person, if such
commercial paper has, at the time of the Company's or any Subsidiary's
investment therein or contractual commitment providing for such investment,
credit ratings of A-1 by S&P and P-1 by Moody's; and (b) money market mutual or
similar funds having assets in excess of $100,000,000.

         "Change of Control" means (i) an event or series of events by which
any Person or other entity or group of Persons or other entities acting in
concert as a partnership or other group (a "Group of Persons") other than the
Lawrence Group or any member thereof shall, as a result of a tender or exchange
offer, open market purchases, privately negotiated purchases, merger,
consolidation or otherwise, have become the beneficial owner (within the
meaning of Rule 13d-3 under the Exchange Act) of 40% or more of the combined
voting power of the then outstanding Voting Stock of the Company, (ii) during
any period of two consecutive years, Continuing Directors cease for any reason
to constitute a majority of the Board of Directors then in office, (iii) the
direct or indirect sale, lease, exchange or other transfer of all or
substantially all of the assets of the Company and the Subsidiaries, taken as a
whole, to any Person or Group of Persons other than the Company or any
Subsidiary Guarantor that is a Wholly Owned Subsidiary, or (iv) the liquidation
or dissolution of the Company.

         "Company" means the party named as such above, until a successor
replaces such Person in accordance with the terms of this Indenture, and
thereafter means such successor.

         "Company Properties" means all Properties, and equity, partnership or
other ownership interests therein, that are related or incidental to, or used
or useful in connection with, the conduct or operation of any business
activities of the Company or the Subsidiaries, which business activities are
not prohibited by the terms of this Indenture.

         "Consolidated EBITDA" means, with respect to any Person for any
period, the Consolidated Net Income of such Person for such period increased
(to the extent deducted in determining Consolidated Net Income) by the sum of:
(i) all income taxes of such Person and its subsidiaries paid or accrued
according to GAAP for such period (other than income taxes attributable to
extraordinary, unusual or non-recurring gains or losses), (ii) all interest
expense of such Person and its subsidiaries paid or accrued in accordance with
GAAP for such period (including amortization of original issue discount and the
interest portion of deferred payment obligations), (iii) depreciation and
depletion of such Person and its subsidiaries, (iv) amortization of such Person
and its subsidiaries including, without limitation, amortization of capitalized
debt issuance costs and (v) any other non-cash charges to the extent deducted
from Consolidated Net Income.



                                      -4-

<PAGE>   10
         "Consolidated EBITDA Coverage Ratio" means, with respect to any
Person, the ratio of (1) Consolidated EBITDA of such Person for the period (the
"Pro Forma Period") consisting of the most recent four full fiscal quarters for
which financial information in respect thereof is available immediately prior
to the date of the transaction giving rise to the need to calculate the
Consolidated EBITDA Coverage Ratio (the "Transaction Date") to (2) the
aggregate Fixed Charges which such Person will accrue during the fiscal quarter
in which the Transaction Date occurs and the three fiscal quarters immediately
subsequent to such fiscal quarter (the "Forward Period") on the aggregate
amount of Indebtedness outstanding on the Transaction Date, including any
Indebtedness proposed to be incurred on such date and excluding any
Indebtedness repaid with the proceeds of such Indebtedness (as though all such
Indebtedness was incurred or repaid on the first day of the quarter in which
the Transaction Date occurred). In addition to, but without duplication of, the
foregoing, for purposes of this definition, "Consolidated EBITDA" shall be
calculated after giving effect (without duplication), on a pro forma basis for
the Pro Forma Period (but no longer), to (i) any Investment, during the period
commencing on the first day of the Pro Forma Period to and including the
Transaction Date (the "Reference Period"), in any other Person that, as a
result of such Investment, becomes a subsidiary of such Person, (ii) the
acquisition, during the Reference Period (by merger, consolidation or purchase
of stock or assets) of any business or assets, which acquisition is not
prohibited by this Indenture, including but not limited to Permitted Industry
Investments, as if such acquisition had occurred on the first day of the
Reference Period, (iii) any sales or other dispositions of assets occurring
during the Reference Period, in each case as if such incurrence, Investment,
repayment, acquisition or asset sale had occurred on the first day of the
Reference Period and (iv) interest income reasonably anticipated by the Company
to be received during the Pro Forma Period from Investments in Cash
Equivalents, which Investments exist on the Transaction Date or will exist as a
result of the transaction giving rise to the need to calculate the Consolidated
EBITDA Coverage Ratio. For purposes of this definition, "Fixed Charges" shall
be calculated after giving effect (without duplication), on a pro forma basis
for the Forward Period, to any Indebtedness incurred or repaid on or after the
first day of the Forward Period and prior to the Transaction Date. For purposes
of calculating the Company's Consolidated EBITDA Coverage Ratio, Indebtedness
of a Subsidiary that is not a Wholly Owned Subsidiary (which Indebtedness is
non-recourse to the Company or any other Subsidiary or any of their assets)
shall be included only to the extent of the Company's pro rata ownership
interest in such Subsidiary. 

         "Consolidated Net Income" of any Person means, for any period, the
aggregate net income (or loss) of such Person and its subsidiaries for such
period on a consolidated basis, determined in accordance with GAAP, provided
that (i) the net income of (a) any Unrestricted Subsidiary and (b) any other
Person in which such Person or any subsidiary thereof has an interest (which
interest, in the case of those Persons referred to in clause (b), does not
cause the net income of such other Person to be consolidated with the net
income of such Person in accordance with GAAP) will be included only to the
extent of the amount of dividends or distributions actually paid in cash or
Cash Equivalents to such Person or its subsidiaries that are Subsidiary
Guarantors by such other Person in such period; (ii) the net income of any
subsidiary of such Person that is subject to any Payment Restriction will be
excluded to the extent of such Payment Restriction; and (iii) (a) the net
income (or loss) of any other Person acquired in a pooling of interests
transaction for any period prior to the date of such acquisition, (b) any net
gain (but not loss) on the sale or other disposition by such Person or any of
its subsidiaries of assets and of the Capital Stock of any subsidiary of such
Person, (c) items which are extraordinary, and (d) the cumulative effect of a
change in accounting principles, will each be excluded.

         "Consolidated Net Tangible Assets" as of any date means with respect
to any Person the Consolidated Net Worth of such Person and its consolidated
Subsidiaries as of such date less (i) all write-ups subsequent to the date of
this Indenture in the book value of any asset owned by such Person 



                                      -5-

<PAGE>   11
or a consolidated Subsidiary of such Person (other than purchase accounting
adjustments made, in connection with any acquisition of any entity that becomes
a consolidated Subsidiary of such Person after the date of this Indenture to
the book value of the assets of such entity), (ii) all Investments as of such
date in unconsolidated Subsidiaries and in Persons that are not Subsidiaries
(except, in each case, Permitted Investments), (iii) all unamortized goodwill,
trademarks, trade names, service marks, brand names, copyrights, patents and
other intangible assets in accordance with GAAP, and (iv) unamortized debt
discount and expense and unamortized deferred charges of such date, all of the
foregoing determined in accordance with GAAP.

         "Consolidated Net Worth" as of any date means with respect to any
Person the amount by which the assets of such Person and its subsidiaries on a
consolidated basis exceed (i) the total liabilities of such Person and its
subsidiaries on a consolidated basis, plus (ii) Disqualified Capital Stock of
such Person or Disqualified Capital Stock of any subsidiary of such Person
issued to any Person other than such Person or another wholly-owned subsidiary
of such Person, in each case determined in accordance with GAAP.

         "Continuing Directors" means any member of the Board of Directors of
the Company on the Issue Date, any director elected since the date thereof in
any annual meeting of the stockholders upon the recommendation of the Board of
Directors of the Company and any other member of the Board of Directors of the
Company who will be recommended or elected to succeed a Continuing Director by
a majority of Continuing Directors who are then members of the Board of
Directors of the Company.

         "Credit Facility" means one or more credit facilities without
limitation as to amount that now is or are or hereafter may be entered into
among the Company or one or more of its Subsidiaries or the Company and one or
more of its Subsidiaries, as the case may be, and the lenders parties thereto,
including any related notes, guarantees, collateral documents, and other
instruments and agreements executed in connection therewith without limitation
as to amount, which term, as of the Issue Date, initially consists of the Third
Amended and Restated Loan Agreement by and among Company, the financial
institutions party thereto and Wells Fargo Bank (Texas), National Association,
as agent, and in each case as amended, modified, supplemented, renewed,
extended, refunded, replaced, restated or refinanced from time to time in whole
or part in one or more credit agreements, loan agreements, instruments or
similar agreements without limitation as to amount, as such may be further
amended, modified, supplemented, extended, refunded, restated, replaced,
renewed or refinanced from time to time.

         "Currency Agreement" means the obligations of any Person pursuant to
any foreign exchange contract, currency swap agreement or other similar
agreement or arrangement designed to protect such Person or any of its
subsidiaries against fluctuations in currency values.

         "Default" means any event which is, or after notice or passage of time
would be, an Event of Default.

         "Disqualified Capital Stock" means, with respect to any Person, any
Capital Stock of such Person or its subsidiaries that, by its terms, by the
terms of any agreement related thereto or by the terms of any security into
which, mandatorily or at the option of the holder, it is convertible or
exchangeable, is, or upon the happening of an event or the passage of time
would be, required to be redeemed or repurchased by such Person or its
subsidiaries, including at the option of the holder, in whole or in part, or
has, upon the happening of an event or the passage of time would have, a
redemption or similar payment due, in each such case on or prior to the
Maturity Date.


                                      -6-

<PAGE>   12
         "Employee Stock Repurchases" means purchases by the Company of any of
its Capital Stock from officers and other employees for the purpose of enabling
such employees to pay personal income tax obligations with the proceeds;
provided that the aggregate amount of all such purchases shall not exceed
$500,000 during any fiscal year of the Company.

         "Equity Interests" means Capital Stock or other equity interests and
all warrants, options or other rights to acquire Capital Stock or other equity
interests.

         "Exchange Act" means the Securities Exchange Act of 1934, as amended,
and the rules and regulations promulgated by the SEC thereunder.

         "Exchange Offer" means the offer by the Company, pursuant to an
effective registration statement filed with the SEC, to exchange for any and
all of the Series A Securities a like aggregate principal amount of Series B
Securities in accordance with the terms and provisions of the Registration
Rights Agreement.

         "Exchange Offer Consummation Date" means the date on which the
Exchange Offer is consummated in accordance with the terms and provisions of
the Registration Rights Agreement.

         "Exempt Foreign Subsidiary" means (i) any Subsidiary engaged in
business permitted under this Indenture exclusively outside the United States
of America, irrespective of its jurisdiction of incorporation and (ii) any
other Subsidiary whose assets (excluding any cash and Cash Equivalents) consist
exclusively of Capital Stock or Indebtedness of one or more Subsidiaries
described in clause (i) of this definition, that, in any case, is so designated
by the Company in an Officers' Certificate delivered to the Trustee and (a) is
not a guarantor of, and has not granted any Lien to secure, the Credit Facility
or any other Indebtedness of the Company or any Subsidiary other than another
Exempt Foreign Subsidiary and (b) does not have total assets that, when
aggregated with the total assets of any other Exempt Foreign Subsidiary, exceed
25% of the Company's consolidated total assets, as determined in accordance
with GAAP, as reflected on the Company's most recent quarterly or annual
balance sheet. The Company may revoke the designation of any Exempt Foreign
Subsidiary by notice to the Trustee.

         "Fixed Charges" means, with respect to any Person, for any period, the
aggregate amount of (i) interest, whether expensed or capitalized, paid,
accrued or scheduled to be paid or accrued during such period (except to the
extent accrued in a prior period) in respect of all Indebtedness of such Person
and its consolidated subsidiaries (including (a) original issue discount on any
Indebtedness and (b) the interest portion of all deferred payment obligations,
calculated in accordance with the effective interest method, in each case to
the extent attributable to such period) and (ii) dividend requirements on
Disqualified Capital Stock of such Person and its consolidated subsidiaries
(whether in cash or otherwise (except dividends payable in shares of Qualified
Capital Stock) (non-cash dividends being valued as determined in good faith by
the Board of Directors of such Person, as evidenced by a Board Resolution))
paid, accrued or scheduled to be paid or accrued during such period (except to
the extent accrued in a prior period) and excluding items eliminated in
consolidation.

         For purposes of the definition of Fixed Charges, (i) interest on a
Capitalized Lease Obligation shall be deemed to accrue at an interest rate
reasonably determined by the Board of Directors of such Person (as evidenced by
a Board Resolution) to be the rate of interest implicit in such Capitalized
Lease Obligation in accordance with GAAP; (ii) interest on Indebtedness that is
determined on a fluctuating basis shall be deemed to have accrued at a fixed
rate per annum equal to the rate of interest of such Indebtedness in effect on
the date Fixed Charges are being calculated, subject to the proviso in the




                                      -7-

<PAGE>   13
following clause (iii); (iii) interest on Indebtedness that may optionally be
determined at an interest rate based upon a factor of a prime or similar rate,
a eurocurrency interbank offered rate, or other rate, shall be deemed to have
been based upon the rate actually chosen, or, if none, then based upon such
optional rate chosen as the Company may designate, (provided that, for the
period following the date on which the rate actually chosen ceases to be in
effect, the Company may designate an optional rate other than that actually
chosen, which optional rate shall be deemed to accrue at a fixed per annum
equal to the rate of interest on such optional rate in effect on the date Fixed
Charges are being calculated); and (iv) Fixed Charges shall be increased or
reduced by the net cost (including amortization of discount) or benefit
associated with obligations under Interest Rate Agreements attributable to such
period.

         "GAAP" means generally accepted accounting principles as in effect in
the United States of America as of any date of determination.

         "Guarantor Senior Indebtedness" means all Indebtedness of a Subsidiary
Guarantor (present and future) created, incurred, assumed or guaranteed by the
Subsidiary Guarantor (and all renewals, extensions, increases or refundings
thereof) (including the principal of, interest on and fees, premiums, expenses
(including costs of collection), indemnities and other amounts payable in
connection with such Indebtedness, and including any Post- Commencement
Amounts), unless the instrument governing such Indebtedness expressly provides
that such Indebtedness is not senior or superior in right of payment to the
Subsidiary Guarantee. Notwithstanding the foregoing, Guarantor Senior
Indebtedness does not include (i) any Indebtedness of the Subsidiary Guarantor
to the Company or any Subsidiary or any Unrestricted Subsidiary, and (ii) any
amounts payable or other liabilities to trade creditors.

         "Holder" means a Person in whose name a Security is registered on the 
Registrar's books.

         "Indebtedness" means, with respect to any Person, without duplication,
any liability, contingent or otherwise, of such Person (i) for borrowed money
(whether or not the recourse of the lender is to the whole of the assets of
such Person or only to a portion thereof), (ii) evidenced by bonds, notes,
debentures or similar instruments, (iii) representing the deferred and unpaid
balance of the purchase price of any property or interest therein (other than
any such balance that represents an account payable or any other monetary
obligation to a trade creditor created, incurred, assumed or guaranteed by such
Person in the ordinary course of business of such Person in connection with
obtaining goods, materials or services and due within twelve months (or such
longer period for payment as is customarily extended by such trade creditor) of
the incurrence thereof, which account is not overdue by more than 150 days,
according to the original terms of sale, unless such account payable is being
contested in good faith or has been extended), (iv) for the payment of a
Capitalized Lease Obligation of such Person, (v) with respect to the
reimbursement of any letter of credit, banker's acceptance or similar credit
transaction, (vi) with respect to Indebtedness (as otherwise defined in this
definition) of another Person secured by a Lien on any asset of such Person,
whether or not such Indebtedness is assumed by such Person (provided that if
the obligations so secured have not been assumed in full by such Person or are
not otherwise such Person's legal liability in full, then such obligations
shall be deemed to be in an amount equal to the greater of (A) the lesser of
(1) the full amount of such obligations, and (2) the fair market value of such
assets, as determined in good faith by the Board of Directors of such Person,
which determination shall be evidenced by a Board Resolution, and (B) the
amount of obligations as have been assumed by such Person or which are
otherwise such Person's legal liability), (vii) to the extent not otherwise
included, under Currency Agreements and Interest Rate Agreements entered into
other than in the ordinary course of such Person's business, (viii) in the case
of such Person, the liquidation preference and any mandatory redemption payment
obligations in respect of Disqualified Capital Stock, and, in the case of a
subsidiary of such Person, the liquidation preference and any mandatory
redemption 



                                      -8-

<PAGE>   14
payment obligations in respect of preferred stock of such subsidiary, and (ix)
in respect of all Indebtedness of others which such Person has guaranteed,
endorsed with recourse (otherwise than for collection, deposit or other similar
transactions in the ordinary course of business), agreed to purchase or
repurchase or in respect of which such Person has agreed contingently to supply
or advance funds or for which such Person has otherwise become liable;
provided, however, Indebtedness arising pursuant to clause (iii) of this
definition as a result of such account payable becoming overdue by more than
150 days shall only be deemed to be incurred at a time when Indebtedness, other
than such Indebtedness, is incurred.

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

         "Independent Director" means any director of the Company who is
neither (i) an executive officer or an employee of the Company or of any of its
Subsidiaries or Affiliates, nor (ii) a Related Person.

         "Institutional Accredited Investor" means an institution that is an
"accredited investor" as that term is defined in Rule 501(a)(1), (2), (3) or
(7) under the Securities Act.

         "Insolvency or Liquidation Proceeding" means, with respect to any
Person, (a) an insolvency or bankruptcy case or proceeding, or any
receivership, liquidation, reorganization proceeding or other similar case or
proceeding, relative to such Person or to its creditors, as such, or its
assets, (b) any liquidation, dissolution or reorganization proceeding of such
Person, whether voluntary or involuntary and whether or not involving
insolvency or bankruptcy, or (c) any assignment for the benefit of creditors or
any other marshalling of assets and liabilities of such Person.

         "Interest Rate Agreement" means the obligations of any Person pursuant
to any interest swap agreement, interest rate collar agreement or other similar
agreement or arrangement designed to protect such Person or any of its
subsidiaries against fluctuations in interest rates.

         "Investment" means, in respect of any Person, any investment in
another Person, whether by means of a share purchase, capital contribution,
loan, advance (other than advances to employees for moving and travel expenses,
drawing accounts and similar expenditures in the ordinary course of business)
or similar credit extension constituting Indebtedness of such other Person and
any guaranty of Indebtedness of any other Person; provided that the following
shall not constitute Investments: (a) extension of trade credit or other
advances to customers on commercially reasonable terms in accordance with
normal trade practices or otherwise in the ordinary course of business, (b)
obligations under Interest Rate Agreements and Currency Agreements, but only to
the extent that the same constitute Permitted Indebtedness, (c) endorsements of
negotiable instruments and documents in the ordinary course of business, (d) an
acquisition of assets, Capital Stock or other securities by the Company or any
of its Subsidiaries for consideration consisting of Capital Stock or other
common equity securities of the Company or any of its Subsidiaries, and (e)
stock, obligations and other securities received in settlement of debts owing
to the Company or any of its Subsidiaries as a result of collection efforts or
proceedings or upon the foreclosure or enforcement of any Lien in favor of the
Company or any such Subsidiary, in each case, as to debt owing to the Company
or any such Subsidiary that arose in the ordinary course of business of the
company or any such Subsidiary. For purposes of Section 4.11 and the definition
of Permitted Unrestricted Subsidiary Investments, (i) an "Investment" in an
Unrestricted Subsidiary shall be deemed to include and be valued at the fair
market value of the net assets of any Subsidiary at the time that such
Subsidiary is designated an Unrestricted Subsidiary, and (ii) any Investment in
an Unrestricted Subsidiary shall be valued at fair market value at the time of
such Investment (except, however, when such Investment consists of a loan or
advance by a Person to another Person that is of an intercompany 




                                      -9-

<PAGE>   15
or similar nature between such Persons and arises pursuant to an agreement or
understanding in the ordinary course of business relating to tax sharing,
administrative or similar arrangements, then such Investment shall be valued at
fair market value at the time that the investing Person shall have paid monies
or transferred other consideration to another Person for the benefit of the
Person in whom the agreement to make such loan or advance was made), in each
case as determined by the Board of Directors of the Company and such
Subsidiary, as applicable, in good faith.

         "Issue Date" means the date of first issuance of the Series A
Securities under this Indenture.

         "Lawrence Group" means Lawrence Industries, Inc., J.D. Lawrence and
any Person related to J.D. Lawrence within the second degree of consanguinity,
any trust for the benefit of one or more of such Persons, and any Person
controlled directly or indirectly by any such Person.

         "Lien" means, with respect to any Person, any mortgage, pledge, lien,
encumbrance, easement, restriction, covenant, right-of-way, charge or adverse
claim affecting title or resulting in an encumbrance against real or personal
property of such Person, or a security interest of any kind (including any
conditional sale or other title retention agreement, any lease in the nature
thereof, any option, right of first refusal or other similar agreement to sell,
in each case securing obligations of such Person and any filing of or agreement
to give any financing statement under the Uniform Commercial Code (or
equivalent statute or statutes) of any jurisdiction).

         "Material Subsidiary" means any Subsidiary of the Company which, as of
the relevant date of determination, would be a "significant subsidiary" as
defined in Reg. ss. 230.405 promulgated pursuant to the Securities Act as in
effect on the Issue Date, assuming the Company is the "registrant" referred to
in such definition, except that the 10% amounts referred to in such definition
shall be deemed to be 5%.

         "Maturity Date" means August 15, 2007.

         "Moody's" means Moody's Investors Service, Inc. and its successors.

         "Net Available Proceeds" means the aggregate cash proceeds received by
the Company or any of its Subsidiaries in respect of any Asset Sale (including,
without limitation, any cash proceeds received upon the sale or other
disposition of, or payments or collections on, any non-cash consideration
received in any Asset Sale, provided that such sale or other disposition was
contemplated by the Company or its applicable Subsidiary in connection with, and
was consummated incident to, such Asset Sale, and in respect to each of the
foregoing receipts of cash proceeds only as and when received, and excluding any
other consideration until such time as such consideration is converted into, and
received by the Company or any of its Subsidiaries as, cash), net of all (i)
legal, accounting and investment banking fees and expenses, sales commissions,
relocation, transportation, handling and storage expenses, title, recording and
if applicable, release expenses and other fees and expenses incurred as a result
of such Asset Sale, (ii) taxes paid or payable as a result of such Asset Sale or
required to be accrued as a liability as a consequence thereof (after taking
into account any available and applicable tax credits or deductions and any
applicable tax sharing arrangements), (iii) amounts required to be applied to
the repayment of Indebtedness secured by a Lien on the asset or assets that were
the subject of such Asset Sale, (iv) amounts required to be paid to any Person
(other than the Company or any Subsidiary) owning a beneficial interest in the
asset or assets that were the subject of such Asset Sale, (v) amounts required
to be paid in order to obtain a necessary consent to such Asset Sale or by
applicable law, and (vi) reserves to adjustments in respect of the sale price of
such asset or assets established in accordance with GAAP.


                                      -10-

<PAGE>   16
         "Net Proceeds" means (i) in the case of any sale by the Company of
Qualified Capital Stock, the aggregate net cash proceeds received by the
Company, after payment of expenses, commissions and the like incurred in
connection therewith, and (ii) in the case of any exchange, exercise,
conversion or surrender of any outstanding securities or Indebtedness of the
Company for or into shares of Qualified Capital Stock of the Company, the net
book value of such outstanding securities or Indebtedness as adjusted on the
books of the Company on the date of such exchange, exercise, conversion or
surrender (plus any additional amount required to be paid by the holder of such
Indebtedness or securities to the Company upon such exchange, exercise,
conversion or surrender and less any and all payments made to the holders of
such Indebtedness or securities, and all other expenses incurred by the Company
in connection therewith).

         "Non-Recourse Indebtedness" means Indebtedness (i) as to which neither
the Company nor any of its Subsidiaries (a) provides credit support of any kind
(including any undertaking, agreement or instrument that would constitute
Indebtedness), (b) is directly or indirectly liable (as a Subsidiary Guarantor
or otherwise), or (c) constitutes the lender unless otherwise permitted under
this Indenture; and (ii) no default with respect to which (including any rights
that the holders thereof may have to take enforcement action against an
Unrestricted Subsidiary) would permit (upon notice, lapse of time or both) any
holder of any other Indebtedness of the Company or any of its Subsidiaries to
declare pursuant to the express terms governing such Indebtedness a default on
such other Indebtedness or cause the payment thereof to be accelerated or
payable prior to its stated maturity.

         "Obligations" mean the due and punctual payment of principal of and
interest on the Securities when due, whether at maturity, by acceleration, by
redemption or otherwise, and all other monetary obligations of the Company
under this Indenture and the Securities and the due and punctual performance of
all other obligations of the Company under this Indenture and the Securities.

         "Officer" means, with respect to any Person, the Chairman of the
Board, the President, any Vice President, the Chief Financial Officer or the
Treasurer of such Person.

         "Officers' Certificate" means, with respect to any Person, a
certificate signed by two Officers or by an Officer and either a Secretary,
Assistant Secretary or Assistant Treasurer of such Person.

         "Opinion of Counsel" means a written opinion from legal counsel who is
reasonably acceptable to the Trustee. The counsel may be an employee of or
counsel to the Company (or any Subsidiary Guarantor, if applicable).

         "Permitted Indebtedness" means (i) Indebtedness under the Series A
Securities and any Series B Securities issued in exchange for Series A
Securities of equal principal amount; (ii) Indebtedness from time to time
outstanding under the Credit Facility in an aggregate principal amount at any
one time outstanding not to exceed the greater of (a) the sum of (1) 85%
of accounts receivable (net of any related reserves) of the Company and its
Subsidiaries plus (2) 50% of the revenue-producing tools and inventory of the
Company and its Subsidiaries, as such amounts are determined on a consolidated
basis in accordance with GAAP and reflected on the Company's most recent
balance sheet prepared in accordance with GAAP, or (b) $30.0 million, plus all
interest and fees under such agreements and any guarantee of any such
Indebtedness; (iii) the Subsidiary Guarantees of the Securities (and any
assumption of the obligations guaranteed thereby); (iv) Permitted Refinancing
Indebtedness; (v) Indebtedness of the Company to any Wholly Owned Subsidiary,
and any Indebtedness of any Wholly Owned Subsidiary to the Company or to any
Wholly Owned Subsidiary; provided, that in each case, such Indebtedness has not
been incurred in contemplation of any subsequent issuance or transfer of any
Capital Stock or any other 



                                      -11-

<PAGE>   17
event which would result in any such Wholly Owned Subsidiary ceasing to be a
Wholly Owned Subsidiary or any other subsequent transfer of any such
Indebtedness (except to the Company or a Wholly Owned Subsidiary), and if
incurred in contemplation of any of the foregoing events, then such
Indebtedness shall be deemed to be incurred and shall be treated as an
incurrence of Indebtedness for purposes of Section 4.09 at the time the Wholly
Owned Subsidiary in question ceased to be a Wholly Owned Subsidiary; (vi)
Permitted Operating Obligations; (vii) other Indebtedness outstanding at any
time in an aggregate principal amount not to exceed $5.0 million; and (viii)
Indebtedness outstanding on the Issue Date. Permitted Refinancing Indebtedness
that constitutes a refinancing of amounts referred to in clauses (ii) and (vii)
shall be deemed to be incurred pursuant to and subject to the limitations in
clauses (ii) and (vii), respectively. The Company may elect at any time that
amounts of Indebtedness incurred under clauses (ii) or (vii) be deemed to be
incurred pursuant to the first paragraph of Section 4.09 (if then permitted to
be so incurred), in which event such amounts so incurred shall be deemed not to
be incurred under clause (ii) or (vii); provided, however, any such
Indebtedness deemed not to be incurred under clause (ii) shall still be treated
as Indebtedness under and governed by the Credit Facility for purposes of all
other provisions of this Indenture.

         "Permitted Industry Investments" means (i) capital expenditures,
including, without limitation, acquisitions of Company Properties and interests
therein; (ii) exchanges of Company Properties for other Company Properties of
at least equivalent value as determined in good faith by the Board of Directors
of the Company; (iii) Investments by the Company or any Subsidiary in any
Subsidiary (or in any Person that becomes a Subsidiary as a result of such
Investment) that are not subject to any Payment Restriction; and (iv)
Investments by the Company or any Subsidiary in any Person of which less than
50% of the issued and outstanding Equity Interests is owned by the Company or
another Subsidiary of the Company; provided that the aggregate of all
Investments by the Company and any Subsidiary pursuant to this clause (iv)
shall at not time exceed 15% of the Consolidated Net Tangible Assets of the
Company.

         "Permitted Investments" means Cash Equivalents and Permitted Industry
Investments (in each case, other than Investments in Unrestricted
Subsidiaries).

         "Permitted Liens" means (i) Liens for taxes, assessments and
governmental charges not yet delinquent or being contested in good faith and
for which such adequate reserves have been established to the extent required
by GAAP, (ii) landlord's, carriers, warehouseman's, storage, mechanics',
workmen's, materialmen's, operator's or similar Liens arising in the ordinary
course of business, (iii) easements, rights-of-way, restrictions and other
similar encumbrances incurred in the ordinary course of business and
encumbrances consisting of zoning restrictions, easements, licenses,
restrictions on the use of Company Properties or minor imperfections in title
thereto which, in the aggregate, are not material in amount, and which do not
in any case materially detract from the Company Properties subject thereto or
interfere with the ordinary conduct of the business of the Company or the
Subsidiaries, (iv) Liens on Company Properties which arise out of operation of
law, (v) judgment and attachment Liens not giving rise to an Event of Default
or Liens created by or existing from any litigation or legal proceeding that
are currently being contested in good faith by appropriate proceedings and for
which adequate reserves have been made, (vi) (a) Liens upon any Property of any
Person existing at the time of acquisition thereof by the Company or any
Subsidiary, (b) Liens upon any Property of a Person existing at the time such
Person is merged or consolidated with the Company or any Subsidiary or existing
at the time of the sale or transfer of any such Property of such Person to the
Company or any Subsidiary, or (c) Liens upon any Property of a Person existing
at the time such Person becomes a Subsidiary; provided that in each case such
Lien has not been created in contemplation of such sale, merger, consolidation,
transfer or acquisition, and provided further that in each such case no such
Lien shall extend to or cover any Property of the Company or any Subsidiary
other than the Property being 




                                      -12-

<PAGE>   18
acquired and improvements thereon, (vii) Liens existing on the Issue Date,
(viii) Liens on deposits made in the ordinary course of business, including,
without limitation, pledges or deposits under worker's compensation,
unemployment insurance and other social security legislation and deposits to
secure the performance of bids, trade contracts (other than for borrowed
money), leases, statutory obligations, surety and appeal bonds, performance
bonds and other obligations of a similar nature incurred in the ordinary course
of business, (ix) Liens in favor of collecting or payor banks having a right of
setoff, revocation, refund or chargeback with respect to money or instruments
of the Company or any Subsidiary on deposit with or in possession of such bank,
(x) Liens upon any Property which were created solely for the purpose of
securing Indebtedness representing, or incurred to finance, refinance or
refund, the cost (including the cost of construction) of such Property;
provided that (A) no such Lien shall extend to or cover any Property of the
Company or any Subsidiary other than the Property so acquired and improvements
thereon and (B) the Lien securing any such Indebtedness shall be created within
90 days of such acquisition, (xi) Liens securing Indebtedness that constitutes
Permitted Indebtedness pursuant to clause (i), (ii), (iii), (iv) (but only to
the extent secured at the time of such renewal, extension, refunding or
repurchase, and no such Lien shall extend to any other Property of the Company
or any Subsidiary), and (vi) of the definition of Permitted Indebtedness, (xii)
any interest or title of a lessor under any Capitalized Lease Obligation or
operating lease and (xiii) Liens securing obligations under or in respect of
either Currency Agreements or Interest Rate Agreements.

         "Permitted Operating Obligations" means Indebtedness of the Company or
any Subsidiary in respect of one or more standby letters of credit, bid,
performance or surety bonds, or other reimbursement obligations, issued for the
account of, or entered into by, the Company or any Subsidiary in the ordinary
course of business, or in lieu of any thereof or in addition to any thereto,
guarantees and letters of credit supporting any such obligations and
Indebtedness (in each case, other than for an obligation for borrowed money,
other than borrowed money represented by any such letter of credit, bid,
performance or surety bond, or reimbursement obligation itself, or any
guarantee and letter of credit related thereto).  

         "Permitted Refinancing Indebtedness" means (i) Senior Indebtedness of
the Company or any Subsidiary, the net proceeds of which are used solely to
renew, extend, refinance, refund or repurchase outstanding Securities,
including the amount of reasonable fees and expenses and premium, if any,
incurred by the Company or such Subsidiary in connection therewith; or (ii)
Indebtedness of the Company or any Subsidiary, the net proceeds of which are
used to renew, extend, refinance, refund or repurchase (including, without
limitation, pursuant to a Change of Control Offer as required by the terms of
the Securities) outstanding Indebtedness of the Company or any Subsidiary,
provided that (a) if the Indebtedness (including the Securities) being renewed,
extended, refinanced, refunded or repurchased is pari passu with or
subordinated in right of payment to either the Securities or the Subsidiary
Guarantees, then such Indebtedness is pari passu with or subordinated in right
of payment to, as the case may be, the Securities or the Subsidiary Guarantees
at least to the same extent as the Indebtedness being renewed, extended,
refinanced, refunded or repurchased, (b) such Indebtedness is scheduled to
mature no earlier than the Indebtedness being renewed, extended, refinanced,
refunded or repurchased, and (c) such Indebtedness has an Average Life at the
time such Indebtedness is incurred that is greater than the Average Life of the
Indebtedness being renewed, extended, refinanced, refunded or repurchased;
provided, further, that such Indebtedness (to the extent that such Indebtedness
constitutes Permitted Refinancing Indebtedness) is in an aggregate principal
amount (or, if such Indebtedness is issued at a price less than the principal
amount thereof, the aggregate amount of gross proceeds therefrom is) not in
excess of the aggregate principal amount then outstanding of the Indebtedness
being renewed, extended, refinanced, refunded or repurchased (or if the
Indebtedness being renewed, extended, refinanced, refunded or repurchased was
issued at a price less than the principal amount thereof, then not 




                                      -13-

<PAGE>   19
in excess of the amount of liability in respect thereof determined in
accordance with GAAP) plus the amount of reasonable fees and expenses and
premium, if any, incurred by the Company or such Subsidiary in connection
therewith.

         "Permitted Unrestricted Subsidiary Investments" means Investments in
Unrestricted Subsidiaries in a cumulative aggregate amount (in cash or the fair
market value of property other than cash, as determined in good faith by the
Board of Directors of the Company) not to exceed the sum of (i) $10.0 million
and (ii) cash or cash equivalent distributions made from any Unrestricted
Subsidiary and received, after the Issue Date, as such by the Company, provided
that any amount included in this clause (ii) shall be deducted from any amounts
referred to in clause (y)(3) of Section 4.11. Notwithstanding the foregoing,
Permitted Unrestricted Subsidiary Investments shall also include any
Investments in Unrestricted Subsidiaries to the extent such Investment consists
of (a) Qualified Capital Stock of the Company or (b) amounts referred to in
clause (y)(2) of Section 4.11, which Investments shall be excluded from the sum
in the previous sentence, provided that the amount of any Investments pursuant
to this clause (b) shall be deducted from amounts referred to in clause (y)(2)
of Section 4.11.

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

         "Post-Commencement Amounts" means all interest and fees accrued or
accruing after the commencement of any Insolvency or Liquidation Proceeding in
accordance with and at the contract rate (including, without limitation, any
non-usurious rate applicable upon default) and all premiums, expenses
(including costs of collection), indemnities and other amounts that would have
accrued or been incurred after the commencement of any Insolvency or
Liquidation Proceeding in any case as specified in any agreement or instrument
creating, evidencing, or governing any Senior Indebtedness or any Guarantor
Senior Indebtedness, as the case may be, whether or not, pursuant to applicable
law or otherwise, the claim for such interest, fees, premiums, expenses,
indemnities or other amounts is allowed and non-avoidable as a claim in such
Insolvency or Liquidation Proceeding.

         The term "principal" of a debt security means the principal amount of
the security plus the premium, if any, on the security.

         "Private Placement Legend" means the legend initially set forth on the
Securities in the form set forth in Exhibit A attached hereto.

         The term "pro forma" means, with respect to any calculation made or
required to be made pursuant to the terms of this Indenture, a calculation in
accordance with Article 11 of Regulation S-X under the Securities Act, as
amended.

         "Property" means, with respect to any Person, any interest of such
Person in any kind of property or asset, whether real, personal or mixed, or
tangible or intangible, including, without limitation, Capital Stock,
partnership interests and other equity or ownership interests in any other
Person.

         "Public Equity Offering" means an underwritten public offer and sale
of common stock (that is Qualified Capital Stock) of the Company pursuant to a
registration statement that has been declared effective by the SEC pursuant to
the Securities Act (other than a registration statement on Form S-8 or
otherwise relating to equity securities issuable under any employee benefit
plan of the Company).




                                     -14-

<PAGE>   20
         "Purchase Agreement" means the Purchase Agreement dated August 14,
1997 among the Company, the Subsidiary Guarantors and the Purchasers.

         "Purchase Money Obligations" means indebtedness evidenced by a note,
debenture, bond or other security or investment (whether or not secured by any
lien or other security interest) issued to or assumed in favor of a vendor as
all or part of the purchase price of property acquired by the Company or any
Subsidiary; provided, however, that such term shall not include any account
payable or any other indebtedness incurred, created or assumed in the ordinary
course of business in connection with the obtaining of material, products or
services.

         "Purchasers" means the initial purchaser of Series A Securities named
in Schedule I attached to the Purchase Agreement.

         "Qualified Capital Stock" means any Capital Stock that is not
Disqualified Capital Stock.

         "Qualified Institutional Buyer" has the meaning attributed thereto in
Rule 144A under the Securities Act.

         "Registration Default" shall have the meaning ascribed thereto in the
Registration Rights Agreement.

         "Registration Rights Agreement" means the Registration Rights
Agreement dated August 19, 1997, among the Company, the Subsidiary Guarantors
and the Purchasers.

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

         "Related Person" means (i) any Affiliate of the Company, (ii) any
individual or other Person who directly or indirectly holds 10% or more of the
combined voting power of the then outstanding Voting Stock of the Company,
(iii) any relative of any individual referred to in clauses (i), (ii) and (iv)
hereof by blood, marriage or adoption not more remote than first cousin and
(iv) any officer or director of the Company.

         "Representative" means the indenture trustee or other trustee, agent
or representative for any issue of Senior Indebtedness or Guarantor Senior
Indebtedness.

         "Responsible Officer" means, when used with respect to the Trustee,
any officer within the corporate trust department of the Trustee (or any
successor group of the Trustee) or any other officer of the Trustee customarily
performing functions similar to those performed by any of the above designated
officers and also means, with respect to a particular corporate trust matter,
any other officer to whom such matter is referred because of his knowledge of
and familiarity with the particular subject.

         "Restricted Debt Prepayment" means any purchase, redemption,
defeasance (including, but not limited to, in substance or legal defeasance) or
other acquisition or retirement for value, directly or indirectly, by the
Company or a Subsidiary, prior to the scheduled maturity or prior to any
scheduled repayment of principal or sinking fund payment, as the case may be,
in respect of Indebtedness of the Company or any Subsidiary that is subordinate
in right to the Securities or the Subsidiary Guarantees, provided, however,
that any such acquisition shall be deemed not to be a Restricted Debt
Prepayment to the extent it is made (i) in exchange for or with the proceeds
from the substantially concurrent issuance of Qualified Capital Stock or (ii)
in exchange for or with the proceeds from the substantially concurrent 



                                      -15-

<PAGE>   21
issuance of Indebtedness, in a principal amount (or, if such Indebtedness
provides for an amount less than the principal amount thereof to be due and
payable upon the acceleration thereof, with an original issue price) not to
exceed the lesser of (a) the principal amount of Indebtedness being acquired in
exchange therefor (or with the proceeds therefrom) and (b) if such Indebtedness
being acquired was issued at an original issue discount, the original issue
price thereof plus amortization of the original issue discount at the time of
the incurrence of the Indebtedness being issued in exchange therefor (or the
proceeds of which will finance such acquisition), and provided further that any
such Indebtedness shall have an Average Life not less than the Average Life of
the Indebtedness being acquired, and shall contain subordination and default
provisions no less favorable, in any material respect, to holders of the
Securities than those contained in such Indebtedness being acquired.

         "Restricted Payment" means any (i) Stock Payment, (ii) Investment
(other than Permitted Investments and other than Permitted Unrestricted
subsidiary Investments) or (iii) Restricted Debt Prepayment.

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

         "S&P" means Standard & Poor's Ratings Group and its successors.

         "SEC" means the Securities and Exchange Commission.

         "Securities" has the meaning stated in the first recital of this
Indenture and more particularly means any Series A Securities or any Series B
Securities authenticated and delivered under this Indenture.

         "Securities Act" means the Securities Act of 1933, as amended, and the
rules and regulations promulgated thereunder.

         "Senior Indebtedness" means all Indebtedness of the Company (present
and future) created, incurred, assumed or guaranteed by the Company (and all
renewals, extensions or refundings thereof) (including the principal of,
interest on and fees, premiums, expenses (including costs of collection),
indemnities and other amounts payable in connection with such Indebtedness, and
including any Post-Commencement Amounts), unless the instrument governing such
Indebtedness expressly provides that such Indebtedness is not senior or
superior in right of payment to the Securities. Notwithstanding the foregoing,
Senior Indebtedness of the Company does not include (i) any Indebtedness of the
Company to any Subsidiary or any Unrestricted Subsidiary and (ii) any amounts
payable or other liabilities to trade creditors.

         "Series A Securities" means the 9 3/4% Senior Notes due 2007, Series
A, being issued and sold pursuant to the Purchase Agreement and this Indenture.

         "Series B Securities" means the 9 3/4% Senior Notes due 2007, Series
B, being issued and sold pursuant to the Registration Rights Agreement and this
Indenture.

         "Stock Payment" means, with respect to any Person, (a) the declaration
or payment by such Person, either in cash or in property, of any dividend on
(except, in the case of the Company, dividends payable solely in Qualified
Capital Stock of the Company), or the making by such Person or any of its
subsidiaries of any other distribution in respect of, such Person's Capital
Stock or any warrants, rights or options to purchase or acquire shares of any
class of such Capital Stock (except for the issuance of Qualified Capital Stock
pursuant to the exercise thereof), or (b) the redemption, repurchase,
retirement 



                                      -16-

<PAGE>   22
or other acquisition for value by such Person or any of its subsidiaries,
directly or indirectly, of such Person's or any of its subsidiaries' Capital
Stock or any warrants, rights or options to purchase or acquire shares of any
class of such Capital Stock other than, in the case of the Company, through the
issuance in exchange therefor solely of Qualified Capital Stock of the Company;
provided, however, that in the case of a Subsidiary, the term "Stock Payment"
shall not include (i) any such payment with respect to its Capital Stock or
warrants, rights or options to purchase or acquire shares of any class of its
Capital Stock payable to the Company or a Wholly Owned Subsidiary, or (ii)
Employee Stock Repurchases.

         A "subsidiary" of any Person means (i) a corporation a majority of
whose Voting Stock is at the time, directly or indirectly, owned by such
Person, by one or more wholly owned subsidiaries of such Person or by such
Person and one or more wholly owned subsidiaries of such Person, (ii) a
partnership in which such Person or a wholly owned subsidiary of such Person
is, at the date of determination, a general or limited partner of such
partnership, but only if such Person or its wholly owned subsidiary is entitled
to receive more than fifty percent of the assets of such partnership upon its
dissolution, or (iii) any other Person (other than a corporation or
partnership) in which such Person, a wholly owned subsidiary of such Person or
such Person and one or more wholly owned subsidiaries of such Person, directly
or indirectly, at the date of determination thereof, has (x) at least a
majority ownership interest or (y) the power to elect or direct the election of
a majority of the directors or other governing body of such Person.

         "Subsidiary" means any subsidiary of the Company; provided, that an
Unrestricted Subsidiary shall not be deemed a subsidiary of the Company for
purposes of this Indenture.

         "Subsidiary Guarantee" means, individually and collectively, the
guarantees given by the Subsidiary Guarantors pursuant to Article Ten,
including a notation in the Securities substantially in the form attached
hereto as Exhibit A-1.

         "Subsidiary Guarantor" means (i) Dailey International, Inc., a
Delaware corporation; Dailey International Sales Corporation, a Delaware
corporation; Columbia Petroleum Services Corp., a Delaware corporation;
International Petroleum Services, Inc., a Delaware corporation; Dailey
Environmental Remediation Technologies, Inc., a Texas corporation; Dailey
Worldwide Services, Corp., a Texas corporation; Air Drilling International,
Inc., a Delaware corporation; and Air Drilling Services, Inc., a Wyoming
corporation; (ii) each of the Company's Subsidiaries that becomes a guarantor
of the Securities in compliance with the provisions of Article Ten and (iii)
each of the Company's Subsidiaries executing a supplemental indenture in which
such Subsidiary agrees to be bound by the terms of this Indenture.

         "Transfer Restricted Security" has the meaning attributed thereto in
the Registration Rights Agreement; provided, however, that the Trustee shall be
entitled to request and conclusively rely upon an Opinion of Counsel with
respect to whether or not any Security is a Transfer Restricted Security.

         "Trust Indenture Act" or "TIA" means the Trust Indenture Act of 1939,
as amended and in force at the date as of which this Indenture was executed
until such time as this Indenture is qualified under the TIA, and thereafter as
in effect on the date on which this Indenture is qualified under the TIA,
except as provided in Section 9.03.

         "Trust Officer" means any officer or assistant officer within the
corporate trust department of the Trustee assigned by the Trustee to administer
its corporate trust matters.



                                      -17-

<PAGE>   23
         "Trustee" means the party named as such above until a successor
replaces it in accordance with the applicable provisions of this Indenture and
thereafter means the successor.

         "U.S. Legal Tender" means such coin or currency of the United States
as at the time of payment shall be legal tender for the payment of public and
private debts.

         "United States" means the United States of America.

         "Unrestricted Subsidiary" means (i) any subsidiary of the Company
which at the time of determination shall be an Unrestricted Subsidiary (as
designated by the Board of Directors of the Company, as provided below) and
(ii) any subsidiary of an Unrestricted Subsidiary. The Board of Directors of
the Company may designate any Subsidiary (including any newly acquired or newly
formed Subsidiary or a Person becoming a Subsidiary through merger or
consolidation or Investment therein) to be an Unrestricted Subsidiary only if:
(a) such Subsidiary does not own any Capital Stock of, or own or hold any Lien
on any property of, any other Subsidiary of the Company which is not a
Subsidiary of the Subsidiary to be so designated or otherwise an Unrestricted
Subsidiary; (b) all the Indebtedness of such Subsidiary shall at the date of
designation, and will at all times thereafter, consist of Non-Recourse
Indebtedness; (c) the Company certifies that such designation complies with
Section 4.11; and (d) such Subsidiary, either alone or in the aggregate with
all other Unrestricted Subsidiaries, does not operate, directly or indirectly,
all or substantially all of the business of the Company and the Subsidiaries.
Any such designation by the Board of Directors of the Company shall be
evidenced to the Trustee by filing with the Trustee a Board Resolution of the
Board of Directors of the Company giving effect to such designation and an
Officers' Certificate certifying that such designation complied with the
foregoing conditions. If, at any time, such Unrestricted Subsidiary would fail
to meet the foregoing requirements as an Unrestricted Subsidiary, it shall
thereafter cease to be an Unrestricted Subsidiary for purposes of this
Indenture, and any Indebtedness of such Subsidiary shall be deemed to be
incurred as of such date. The Board of Directors of the Company may designate
any Unrestricted Subsidiary to be a Subsidiary; provided that immediately after
giving effect to such designation, the Company could incur at least $1.00 of
additional Indebtedness (excluding Permitted Indebtedness) pursuant to the
first paragraph of Section 4.09 on a pro forma basis taking into account such
designation.

         "Voting Stock" means, with respect to any Person, securities of any
class or classes of Capital Stock in such Person entitling the holders thereof
(whether at all times or only so long as no senior class of stock has voting
power by reason of any contingency) to vote in the election of members of the
board of directors or other governing body of such Person.

         "Wholly Owned Subsidiary" means a Subsidiary to the extent (i) all of
the Capital Stock or other ownership interests in such Subsidiary, other than
any directors' qualifying shares mandated by applicable law, is owned directly
or indirectly by the Company or (ii) such Subsidiary is organized in a foreign
jurisdiction and is required by the applicable laws and regulations of such
foreign jurisdiction to be partially owned by the government of such foreign
jurisdiction or individual or corporate citizens of such foreign jurisdiction
in order for such Subsidiary to transact business in such foreign jurisdiction,
provided that the Company, directly or indirectly, owns the remaining Capital
Stock or ownership interests in such Subsidiary and, by contract or otherwise,
controls the management and business of such Subsidiary and derives the
economic benefits of ownership of such Subsidiary to substantially the same
extent as if such Subsidiary were a Wholly Owned Subsidiary.


                                      -18-

<PAGE>   24



SECTION 1.02.   OTHER DEFINITIONS.
<TABLE>
<CAPTION>
                           TERM                                  DEFINED IN SECTION
     <S>                                                                   <C>
     "Agent Members".................................................      2.07
     "Asset Sale Offer"..............................................      4.12
     "Asset Sale Offer Purchase Date"................................      4.12
     "Asset Sale Offer Trigger Date".................................      4.12
     "Bankruptcy Law"................................................      6.01
     "Change of Control Notice"......................................      4.17
     "Change of Control Offer".......................................      4.17
     "Change of Control Purchase Date"...............................      4.17
     "Change of Control Purchase Price" .............................      4.17
     "Custodian".....................................................      6.01
     "DTC"...........................................................      2.01
     "Event of Default"..............................................      6.01
     "Excess Proceeds"...............................................      4.12
     "Funding Guarantor".............................................     10.05
     "Global Security"...............................................      2.01
     "Legal Holiday".................................................     11.07
     "Offer Amount"..................................................      4.12
     "Offer Period"..................................................      4.12
     "Paying Agent"..................................................      2.03
     "Payment Restriction"...........................................      4.14
     "Physical Securities"...........................................      2.01
     "Project Period"................................................      4.12
     "Registrar".....................................................      2.03
     "Related Party Transaction".....................................      4.15
     "Security Register".............................................      2.06
     "U.S. Government Obligations"...................................      8.02
      
</TABLE>

SECTION 1.03.   INCORPORATION BY REFERENCE OF TRUST INDENTURE ACT.

         Whenever this Indenture refers to a provision of the TIA, the
provision is incorporated by reference in and made a part of this Indenture.
The following TIA terms, if used in this Indenture, have the following
meanings:

                  "indenture securities" means the Securities and the 
                   Subsidiary Guarantees.

                  "indenture security holder" means a Holder.

                  "indenture to be qualified" means this Indenture.

                  "indenture trustee" or "institutional trustee" means the 
                   Trustee.

                  "obligor" on the indenture securities means the Company, the
         Subsidiary Guarantors and any other obligor on the Securities or the
         Subsidiary Guarantees.




                                      -19-

<PAGE>   25
         All other TIA terms used in this Indenture that are defined by the
TIA, defined by TIA reference to another statute or defined by SEC rule have
the meanings assigned to them therein.

SECTION 1.04.              RULES OF CONSTRUCTION.

         Unless the context otherwise requires:

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

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

                  (3)   "or" is not exclusive;

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

                  (5)   any gender used in this Indenture shall be deemed to 
         include the neuter, masculine or feminine genders;

                  (6)   provisions apply to successive events and 
         transactions;

                  (7)   "herein," "hereof" and other words of similar import
         refer to this Indenture as a whole and not to any particular Article,
         Section or other Subdivision, and reference herein to any Article,
         Section or other subdivision thereof shall, without further reference,
         mean such Article, Section or other subdivision of this Indenture,
         unless the context otherwise provides; and

                  (8)    when used with reference to the Securities, the
         expression "of like tenor" refers to Securities of the same series.

                                  ARTICLE TWO

                                 THE SECURITIES

SECTION 2.01.            FORM AND DATING.

         The definitive Securities shall be printed, lithographed or engraved
on steel-engraved borders or may be produced in any other manner, all as
determined by the officers executing such Securities or notations of Subsidiary
Guarantees, as the case may be, as evidenced by their execution of such
Securities or notations of Subsidiary Guarantees, as the case may be.

         Except as indicated in the next succeeding paragraph, Securities
(including the notations thereon relating to the Subsidiary Guarantees and the
Trustee's certificate of authentication) shall be issued initially in the form
of one or more permanent global securities in registered form in substantially
the form set forth in Exhibits A, A-1 and A-2 (each being herein called a
"Global Security") deposited with the Trustee, as custodian for The Depository
Trust Company ("DTC"), duly executed by the Company and authenticated by the
Trustee as hereinafter provided, and each shall bear the legend set forth on
Exhibit A. Subject to the limitation set forth in Section 2.02, the principal
amounts of the Global 



                                      -20-

<PAGE>   26
Securities may be increased or decreased from time to time by adjustments made 
on the records of the Trustee, as custodian for DTC, as hereinafter provided.

         Securities (including the notations thereon relating to the Subsidiary
Guarantees and the Trustee's certificate of authentication) originally issued
and sold in reliance on any exemption from registration under the Securities
Act other than Rule 144A shall be issued, and Securities originally offered and
sold in reliance on Rule 144A may be issued, in the form of permanent
certificated securities in registered form in substantially the form set forth
in Exhibits A and A-1 ("Physical Securities"). The Securities may also have
such insertions, omissions, substitutions and variations as may be permitted by
or consistent with this Indenture. The provisions of Exhibits A, A-1 and A-2
are part of this Indenture. The Securities may have notations, legends and
endorsements required by law, stock exchange rule or usage. The Company shall
approve the form of the Securities and any notation, legend or endorsement on
them, subject to the applicable requirements, if any, of Section 2.06. Each
Security shall be dated the date of its authentication.

         The terms and provisions contained in the Securities and the
Subsidiary Guarantees shall constitute, and are hereby expressly made, a part
of this Indenture and, to the extent applicable, the Company, the Subsidiary
Guarantors and the Trustee, by their execution and delivery of this Indenture,
expressly agree to such terms and provisions and to be bound thereby.

         The Series A Securities and the Series B Securities shall be
considered collectively to be a single class for all purposes of this
Indenture, including, without limitation, waivers, amendments, redemptions and
offers to purchase.

         The Securities shall be issuable only in registered form without
coupons and only in denominations of $1,000 and any integral multiple thereof.

SECTION 2.02.            EXECUTION AND AUTHENTICATION.

         One Officer and the Secretary or an Assistant Secretary of the Company
shall sign the Securities for the Company by manual or facsimile signature. The
Company's seal shall be reproduced on the Physical Securities.

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

         A Security shall not be valid until the Trustee or an authenticating
agent manually signs the certificate of authentication on the Security. The
signature shall be conclusive evidence that the Security has been authenticated
under this Indenture.

         The aggregate principal amount of Series A Securities which may be
authenticated and delivered under this Indenture for original issue is limited
to $115,000,000, and the aggregate principal amount of Series B Securities
which may be authenticated and delivered under this Indenture for original
issue is limited to $115,000,000. The aggregate principal amount of Securities
outstanding at any one time may not exceed $115,000,000 except as provided in
Section 2.08.

         At any time after the execution and delivery of this Indenture, the
Company may deliver Series A Securities executed by the Company and having the
notations of Subsidiary Guarantees executed by the Subsidiary Guarantors to the
Trustee for authentication, together with a request from the Company for 



                                      -21-

<PAGE>   27
the authentication and delivery of such Series A Securities, and the Trustee in
accordance with such request shall authenticate and deliver such Series A
Securities with the notations of Subsidiary Guarantees thereon as provided in
this Indenture. Such request from the Company shall specify the principal
amount of the Series A Securities to be authenticated and the date on which the
original issue of Series A Securities is to be authenticated. In addition, on
or before the Exchange Offer Consummation Date, the Company may deliver Series
B Securities executed by the Company and having the notations of Subsidiary
Guarantees executed by the Subsidiary Guarantors to the Trustee for
authentication, together with a request from the Company for the authentication
and delivery of such Series B Securities, and the Trustee in accordance with
such request shall authenticate and deliver such Series B Securities with the
notations of Subsidiary Guarantees thereon as provided in this Indenture. Such
request from the Company shall specify the principal amount of the Series B
Securities to be authenticated and the date on which the Series B Securities
are to be exchanged for an equal principal amount of Series A Securities.

         In connection with the transfer of an entire Global Security to
beneficial owners pursuant to this Section, the Global Security shall be deemed
to be surrendered to the Trustee for cancellation, and the Company shall
execute, and the Trustee shall upon a request from the Company authenticate and
deliver, to each beneficial owner identified by DTC, in exchange for its
beneficial interest in the Global Security, an equal aggregate principal amount
of Physical Securities of authorized denominations.

         The Holder of a Global Security may grant proxies and otherwise
authorize any Person, including Agent Members and Persons that may hold
interests through Agent Members, to take any action which a Holder is entitled
to take under this Indenture or the Securities.

         The Trustee may appoint an authenticating agent to authenticate
Securities. An authenticating agent may authenticate Securities whenever the
Trustee may do so except on original issuance. Each reference in this Indenture
to authentication by the Trustee includes authentication by such agent. An
authenticating agent has the same rights as an Agent to deal with the Company
or its Affiliates.

SECTION 2.03.            REGISTRAR AND PAYING AGENT.

         The Company shall maintain an office or agency designated pursuant to
Section 4.04 where Securities may be presented for registration of transfer or
for exchange (the "Registrar") and an office or agency designated pursuant to
Section 4.04 where Securities may be presented for payment (the "Paying
Agent"). The Registrar shall keep a register of the Securities and of their
transfer and exchange. The Company may have one or more co-registrars and one
or more additional paying agents. The term "Paying Agent" includes any
additional paying agent.

         The Company shall enter into an appropriate agency agreement with any
Agent not a party to this Indenture. Such agency agreement shall provide for
reasonable compensation for such services. The agreement shall implement the
provisions of this Indenture that relate to such Agent and applicable
provisions of the TIA. The Company shall notify the Trustee of the name and
address of any such Agent and shall furnish the Trustee with an executed
counterpart of any such agency agreement. If the Company fails to maintain or
act as Registrar or Paying Agent, the Trustee shall act as such and shall be
duly compensated therefor.

         The Registrar or a co-registrar and a Paying Agent shall be maintained
by the Company in the City of New York. The Company initially designates the
Trustee as the Registrar and Paying Agent.



                                      -22-

<PAGE>   28
SECTION 2.04.            PAYING AGENT TO HOLD MONEY IN TRUST.

         On or before each due date of the principal, premium (if any) and
interest on any Security, the Company shall deposit with the Paying Agent
immediately available funds sufficient to pay such principal, premium (if any)
and interest becoming due. The Company shall require each Paying Agent other
than the Trustee to hold in trust for the benefit of Holders or the Trustee all
money held by such Paying Agent for the payment of principal, premium (if any)
or interest on the Securities, and to notify the Trustee of any Default by the
Company or any Subsidiary Guarantor in making any such payment. While any such
Default continues, the Trustee may require the Paying Agent to pay all money
held by it to the Trustee. Except as provided in the immediately preceding
sentence, the Company at any time may require a Paying Agent to pay all money
held by it to the Trustee. Upon doing so, such Paying Agent (other than the
Company or a Subsidiary) shall have no further liability for the money. If the
Company or a Subsidiary or any of their Affiliates acts as Paying Agent, it
shall segregate and hold as separate trust funds for the benefit of the Holders
and the Trustee all money held by it as Paying Agent.

SECTION 2.05.            HOLDER LISTS.

         The Trustee shall preserve in as current a form as is reasonably
practicable the most recent list available to it of the name and addresses of
Holders and shall otherwise comply with TIA ss. 312(a). If the Trustee is not
the Registrar, the Company shall furnish or cause to be furnished to the
Trustee at least 5 Business Days before each semiannual interest payment date,
and at such other times as the Trustee may request in writing, a list in such
form and as of such date as the Trustee may reasonably require of the names and
addresses of Holders, and the Company shall otherwise comply with TIA ss.
312(a).

SECTION 2.06.            TRANSFER AND EXCHANGE.

         The Company shall cause to be kept a register (the "Security
Register") in which, subject to such reasonable regulations as it may
prescribe, the Company shall provide for the registration of Securities and of
transfers of Securities. The Security Register shall be in written form or any
other form capable of being converted into written form within a reasonable
time. At all reasonable times and during normal business hours, the Security
Register shall be open to inspection by the Trustee.

         Subject to the provisions of this Section 2.06 and Section 2.07, upon
surrender for registration of transfer of any Security at the office or agency
of the Company designated pursuant to Section 4.04, the Company shall execute,
and the Trustee shall authenticate and deliver, in the name of the designated
transferee or transferees, one or more new Securities of like tenor and of any
authorized denomination and of a like aggregate principal amount, each such
Security having the notation of Subsidiary Guarantees thereon.

         Furthermore, any Holder of a Global Security shall, by acceptance of
such Global Security, be deemed to have agreed that transfers of beneficial
interests in such Global Security may be effected only through a book-entry
system maintained by DTC (or its agent), and that ownership of a beneficial
interest in a Global Security shall be required to be reflected in book-entry
form.

         At the option of any Holder, Securities may be exchanged for other
Securities of like tenor and of any authorized denomination and of a like
aggregate principal amount, upon surrender of the Securities to be exchanged at
the office or agency of the Company designated pursuant to Section 4.04.
Further, as provided in the Registration Rights Agreement and subject to the
limitations set forth therein, at the option of any Holder, Series A Securities
may be exchanged, pursuant to the Exchange Offer, for Series



                                      -23-

<PAGE>   29
B Securities of like aggregate principal amount, upon surrender of the Series A
Securities to be exchanged at such office or agency or otherwise pursuant to
the Exchange Offer. Whenever any Securities are so surrendered for exchange,
the Company shall execute, the Subsidiary Guarantors shall execute notations of
Subsidiary Guarantees on, and the Trustee shall authenticate and deliver, the
Securities which the Holder making the exchange is entitled to receive.

         All Securities and the Subsidiary Guarantees noted thereon issued upon
any registration of transfer or exchange of Securities shall be the valid
obligations of the Company and the respective Subsidiary Guarantors, evidencing
the same debt, and entitled to the same benefits under this Indenture, as the
Securities surrendered upon such registration of transfer or exchange.

         Every Security presented or surrendered for registration of transfer
or for exchange shall (if so required by the Company or the Registrar) be duly
endorsed, or be accompanied by a written instrument of transfer, in form
satisfactory to the Company and the Registrar, duly executed by the Holder
thereof or his attorney duly authorized in writing. As a special condition to
registration of transfer or exchange of any Transfer Restricted Securities
involving removal of a Private Placement Legend (other than pursuant to an
effective registration statement under the Securities Act), the Holder
requesting such registration of transfer or exchange shall furnish the Opinion
of Counsel called for by Section 2.14. The following additional special
conditions shall apply to the indicated types of transfers or exchanges:

                  (a)  Respecting any requested registration of transfer or
         exchange of Transfer Restricted Securities in the form of Physical
         Securities, such Physical Securities shall be accompanied, in the sole
         discretion of the Company, by the following additional information and
         documents, as applicable:

                           (1)  if such Physical Security is being delivered 
                  to the Registrar by a Holder for registration in the name of 
                  such Holder, without transfer, a certification from 
                  such Holder to that effect (in substantially the form of 
                  Exhibit A-3); or

                           (2)  if such Physical Security is being transferred
                  to a Qualified Institutional Buyer in accordance with Rule
                  144A under the Securities Act, a certification to that effect
                  (in substantially the form of Exhibit A-3); or

                           (3)  if such Physical Security is being transferred
                  to an Institutional Accredited Investor, delivery of a
                  certification to that effect (in substantially the form of
                  Exhibit A-3), a Transferee Certificate for Institutional
                  Accredited Investors in the form of Exhibit A-4 and an
                  Opinion of Counsel to the effect that such transfer is in
                  compliance with the Securities Act; or

                           (4)  if such Physical Security is being transferred
                  in reliance on Regulation S, delivery of a certification to
                  that effect (substantially in the form of Exhibit A-3), a
                  Transferor Certificate for Regulation S Transfers in the form
                  of Exhibit A-5 and an Opinion of Counsel to the effect that
                  such transfer is in compliance with the Securities Act; or

                           (5)  if such Physical Security is being transferred
                  in reliance on Rule 144, delivery of a certification to that
                  effect (substantially in the form of Exhibit A-3) and an
                  Opinion of Counsel to the effect that such transfer is in
                  compliance with the Securities Act; or




                                      -24-

<PAGE>   30

                           (6)  if such Physical Security is being transferred
                  in reliance on another exemption from the registration
                  requirements of the Securities Act, a certification to that
                  effect (in substantially the form of Exhibit A-3) and an
                  Opinion of Counsel to the effect that such transfer is in
                  compliance with the Securities Act.

                  (b)  Respecting any requested exchange of a Physical Security
         for a beneficial interest in a Global Security, such Physical Security
         shall be accompanied, in the sole discretion of the Company, by the
         following additional information and documents:

                           (1)  a certification, substantially in the form of 
                  Exhibit A-3, that such Physical Security is being transferred 
                  to a Qualified Institutional Buyer; and

                           (2)  written instructions directing the Registrar to
                  make, or to direct DTC to make, an endorsement on the Global
                  Security to reflect an increase in the aggregate amount of
                  the Securities represented by the Global Security;

         whereupon the Registrar shall cancel such Physical Security and cause,
         or direct DTC to cause, in accordance with the standing instructions
         and procedures existing between DTC and the Registrar, the aggregate
         principal amount of Securities represented by the Global Security to
         be increased accordingly. If no Global Security is then outstanding,
         the Company shall issue and the Trustee shall upon a request from the
         Company authenticate a new Global Security in the appropriate amount.

                  (c) Any Person having a beneficial interest in a Global
         Security may upon request to the Registrar exchange such beneficial
         interest for a Physical Security. Upon receipt by the Registrar of
         written instructions (or such other form of instructions as is
         customary for DTC) from DTC or its nominee on behalf of any Person
         having a beneficial interest in a Global Security and upon receipt by
         the Registrar of a written order or such other form of instructions as
         is customary for DTC or the Person designated by DTC as having such a
         beneficial interest containing registration instructions and, in the
         case of any such transfer or exchange of a beneficial interest in
         Transfer Restricted Securities, the following additional information
         and documents:

                           (1)  if such beneficial interest is being transferred
                  to the Person desig nated by DTC as being the beneficial
                  owner, a certification from such Person to that effect (in
                  substantially the form of Exhibit A-3); or

                           (2)  if such beneficial interest is being transferred
                  to a Qualified Institutional Buyer in accordance with Rule
                  144A under the Securities Act, a certification to that effect
                  (in substantially the form of Exhibit A-3); or

                           (3)  if such beneficial interest is being transferred
                  to an Institutional Accredited Investor, delivery of a
                  certification to that effect (substantially in the form of
                  Exhibit A-3), a Transferee Certificate for Institutional
                  Accredited Investors in the form of Exhibit A-4 and an
                  Opinion of Counsel to the effect that such transfer is in
                  compliance with the Securities Act; or

                           (4)  if such beneficial interest is being transferred
                  in reliance on Regulation S, delivery of a certification to
                  that effect (substantially in the form of Exhibit A-3), a




                                      -25-

<PAGE>   31
                  Transferor Certificate for Regulation S Transfers in the form
                  of Exhibit A-5 and an Opinion of Counsel to the effect that
                  such transfer is in compliance with the Securities Act; or

                           (5)  if such beneficial interest is being transferred
                  in reliance on Rule 144 under the Securities Act, delivery of
                  a certification to that effect (substantially in the form of
                  Exhibit A-3) and an Opinion of Counsel to the effect that
                  such transfer is in compliance with the Securities Act; or

                           (6)  if such beneficial interest is being transferred
                  in reliance on another exemption from the registration
                  requirements of the Securities Act, a certification to that
                  effect (in substantially the form of Exhibit A-3) and an
                  Opinion of Counsel to the effect that such transfer is in
                  compliance with the Securities Act,

         then the Registrar will cause, in accordance with the standing
         instructions and procedures existing between DTC and the Registrar,
         the aggregate principal amount of the Global Security to be reduced
         and, following such reduction, the Company will execute and, upon
         receipt of a request from the Company, the Trustee will authenticate
         and deliver to the transferee a Physical Security. Securities issued
         in exchange for a beneficial interest in a Global Security pursuant to
         this Section 2.06(c) shall be registered in such names and in such
         authorized denominations as DTC, pursuant to instructions from Agent 
         Members or otherwise, shall instruct the Registrar in writing. The 
         Registrar shall deliver such Physical Securities to the Persons in 
         whose names such Physical Securities are so registered.

         No service charge shall be made for any registration of transfer or
exchange or redemption of Securities, but the Company may require payment of a
sum sufficient to cover any tax or other governmental charge that may be
imposed in connection with any registration of transfer or exchange of
Securities, other than exchanges pursuant to the Exchange Offer or Section
2.11, 3.06 or 9.05 not involving any transfer.

         Neither the Trustee, the Registrar nor the Company shall be required
(i) to issue, register the transfer of or exchange any Physical Security during
a period of 30 days before a selection of Securities to be redeemed, or (ii) to
register the transfer of or exchange any Physical Security so selected for
redemption in whole or in part, except the unredeemed portion of any such
Security being redeemed in part.

SECTION 2.07.            BOOK-ENTRY PROVISIONS FOR GLOBAL SECURITIES.

         Each Global Security shall be (i) registered in the name of DTC or its
nominee, (ii) delivered to the Trustee as custodian for DTC and (iii) bear the
legend set forth in Exhibit A-2.

         Members of, or participants in, DTC ("Agent Members") shall have no
rights under this Indenture with respect to any Global Security held on their
behalf by DTC, or the Trustee as its custodian, or under such Global Security,
and DTC may be treated by the Company, the Subsidiary Guarantors, the Trustee
and any agent of the Company, the Subsidiary Guarantors or the Trustee as the
absolute owner of such Global Security for all purposes whatsoever.
Notwithstanding the foregoing, nothing herein shall prevent the Company, the
Subsidiary Guarantors, the Trustee or any agent of the Company, the Subsidiary
Guarantors or the Trustee from giving effect to any written certification,
proxy 



                                      -26-

<PAGE>   32
or other authorization furnished by DTC or shall impair, as between DTC
and its Agent Members, the operation of customary practices governing the
exercise of the rights of a holder of any Security.

         Transfers of a Global Security shall be limited to transfers of such
Global Security in whole, but not in part, to DTC, its successors or their
respective nominees. Interests of beneficial owners in a Global Security may be
transferred or exchanged for Physical Securities in accordance with the rules
and procedures of DTC and the provisions of Section 2.06. In addition, Physical
Securities shall be transferred to all beneficial owners in exchange for their
beneficial interests in a Global Security if, and only if, either (1) DTC
notifies the Company that it is unwilling or unable to continue as depositary
for the Global Security and a successor depositary is not appointed by the
Company within 90 days of such notice, (2) an Event of Default has occurred and
is continuing and the Registrar has received a request from DTC to issue
Physical Securities in lieu of all or a portion of the Global Security (in
which case the Company shall deliver Physical Securities within 30 days of such
request) or (3) the Company determines not to have the Securities represented
by the Global Security and notifies DTC and the Registrar thereof.

         In connection with the transfer of an entire Global Security to
beneficial owners pursuant to this Section, the Global Security shall be deemed
to be surrendered to the Trustee for cancellation, and the Company shall
execute, and the Trustee shall upon request of the Company authenticate and
deliver, to each beneficial owner identified by DTC, in exchange for its
beneficial interest in the Global Security, an equal aggregate principal amount
of Physical Securities of authorized denominations.

         The Holders of a Global Security may grant proxies or otherwise
authorize any Persons, including Agent Members and Persons that may hold
interests through Agent Members, to take any action which a Holder is entitled
to take under this Indenture or the Securities.

SECTION 2.08.            REPLACEMENT SECURITIES.

         If a mutilated Security is surrendered to the Trustee or the Registrar
or if the Holder of a Security claims that the Security has been lost,
destroyed or wrongfully taken, the Company shall issue and the Trustee shall
authenticate a replacement Security if the requirements of the Trustee are met.
An indemnity bond may be required by the Trustee, the Company or any Subsidiary
Guarantor that is sufficient in the judgment of the Company, the Subsidiary
Guarantors and the Trustee to protect the Company, the Subsidiary Guarantors,
the Trustee or any Agent from any loss which any of them may suffer if a
Security is replaced. The Company may charge for its expenses (including fees
and expenses of the Trustee) in replacing a Security.

SECTION 2.09.            OUTSTANDING SECURITIES.

         Securities outstanding at any time are all Securities authenticated by
the Trustee except for those cancelled by it, those delivered to it for
cancellation and those described in this Section 2.09 as not outstanding.
Except as set forth in Section 2.10, a Security does not cease to be
outstanding because the Company, the Subsidiary Guarantors or any of their
respective Subsidiaries or Affiliates holds the Security.

         If a Security is replaced pursuant to Section 2.08, it ceases to be
outstanding and interest on it ceases to accrue unless the Trustee receives
proof satisfactory to it that the replaced Security is held by a bona fide
purchaser.



                                      -27-

<PAGE>   33
         If the principal amount of any Security is considered paid under
Section 4.01, it ceases to be outstanding and interest on it ceases to accrue.

SECTION 2.10.            TREASURY SECURITIES.

         In determining whether the Holders of the required principal amount of
Securities have concurred in any direction, waiver or consent, Securities owned
by the Company, any Subsidiary Guarantor or an Affiliate of the Company shall
be considered as though they are not outstanding, except that for the purposes
of determining whether the Trustee shall be protected in relying on any such
direction, waiver or consent, only Securities which the Trustee actually knows
are so owned shall be so disregarded.

SECTION 2.11.            TEMPORARY SECURITIES.

         Until definitive Securities are ready for delivery, the Company may
prepare and, upon written order of the Company, the Trustee shall authenticate
temporary Securities. Temporary Securities shall be substantially in the form
of definitive Securities but may have variations that the Company considers
appropriate for temporary Securities. Without unreasonable delay, the Company
shall prepare and the Trustee shall authenticate and deliver definitive
Securities in exchange for temporary Securities surrendered to it.

SECTION 2.12.            CANCELLATION.

         The Company or any Subsidiary Guarantor at any time may deliver
Securities to the Trustee for cancellation. The Registrar and Paying Agent
shall forward to the Trustee any Securities surrendered to them for transfer,
exchange or payment. The Trustee shall cancel all Securities surrendered for
registration or transfer, exchange, payment or cancellation and shall destroy
cancelled Securities or retain cancelled Securities in accordance with the
Trustee's standard retention policy unless the Company directs their return to
the Company. Except as provided in Section 2.08, the Company may not issue new
Securities to replace Securities that it has paid or delivered to the Trustee
for cancellation.

         Securities that are mandatorily or optionally redeemed by the Company
or that are purchased by the Company pursuant to an Asset Sale Offer or a
Change of Control Offer, or that are otherwise acquired by the Company, will be
surrendered to the Trustee for cancellation.

SECTION 2.13.            DEFAULTED INTEREST.

         If the Company defaults in a payment of interest on the Securities, it
shall pay the defaulted interest in any lawful manner (plus interest on such
defaulted interest to the extent lawful) to the Persons who are Holders on a
subsequent special record date, in each case at the rate provided in the
Securities and in Section 4.01. The Company shall fix the special record date
and payment date. At least 10 days before the special record date, the Company
shall mail to each Holder a notice that states the special record date, the
payment date and the amount of defaulted interest to be paid.

SECTION 2.14.            PRIVATE PLACEMENT LEGEND.

         (a) All Series A Securities issued hereunder on the Issue Date shall
bear the Private Placement Legend. Upon the transfer, exchange or replacement
of Securities bearing the Private Placement Legend, the Registrar shall deliver
only Securities that bear the Private Placement Legend unless, and the Trustee
is hereby authorized to deliver Securities without the Private Placement Legend



                                      -28-

<PAGE>   34
if, (i) there is delivered to the Trustee an Opinion of Counsel to the effect
that neither such legend nor the related restrictions on transfer are required
in order to maintain compliance with the provisions of the Securities Act, (ii)
such Security has been sold pursuant to an effective registration statement
under the Securities Act, which fact has been certified to the Trustee in an
Officers' Certificate or (iii) notwithstanding the foregoing, upon consummation
of the Exchange Offer, the Company shall issue and the Trustee shall
authenticate the Series B Securities in exchange for the Series A Securities
accepted for exchange in the Exchange Offer, which Series B Securities shall
not bear the Private Placement Legend, and the Registrar shall rescind any
restriction on the transfer of such Securities, in each case unless the Holder
of such Series A Securities is either (A) a broker-dealer, (B) a Person
participating in the distribution of the Series A Securities or (C) a Person
who is an affiliate (as defined in Rule 144A) of the Company. Upon the
transfer, exchange or replacement of Securities not bearing the Private
Placement Legend, the Registrar shall deliver Securities that do not bear the
Private Placement Legend.

         (b) By its acceptance of any Security bearing the Private Placement
Legend, each Holder of such a Security acknowledges the restrictions on
transfer of such Security set forth in this Indenture and in the Private
Placement Legend and agrees that it will transfer such Security only as
provided in this Indenture.

                                 ARTICLE THREE

                                   REDEMPTION

SECTION 3.01.            NOTICE TO TRUSTEE.

         If the Company elects to redeem Securities pursuant to the optional
redemption provisions of paragraph 5 of the Securities, it shall notify the
Trustee in writing of the redemption date, the redemption price and the
principal amount of Securities to be redeemed.

         The Company shall give each notice provided for in this Section 3.01
at least 35 days before the redemption date (unless a shorter notice period
shall be satisfactory to the Trustee). Any notice given pursuant to this
Section 3.01 may be cancelled at any time prior to notice of such redemption
being mailed to any Holder and shall thereby be void and of no effect.

SECTION 3.02.            SELECTION OF SECURITIES TO BE REDEEMED.

         If less than all of the Securities are to be redeemed, the Trustee
shall select the Securities to be redeemed in multiples of $1,000 pro rata, by
lot or by any other method that the Trustee considers fair and appropriate and,
if the Securities are listed on any securities exchange, by a method that
complies with the requirements of such exchange. The Trustee shall make the
selection from outstanding Securities not previously called for redemption. The
Trustee may select for redemption portions of the principal of Securities that
have denominations larger than $1,000. Securities and portions of them it
selects shall be in amounts of $1,000 or whole multiples of $1,000. Provisions
of this Indenture that apply to Securities called for redemption also apply to
portions of Securities called for redemption. The Trustee shall notify the
Company promptly of the Securities or portions of Securities to be called for
redemption.

         The provisions of the first paragraph of this Section 3.02 shall not
apply with respect to any redemption affecting only a Global Security, whether
such Global Security is to be redeemed in whole or in part. In case of any such
redemption in part, the unredeemed portion of the principal amount of the
Global Security shall be in an authorized denomination.


                                      -29-

<PAGE>   35
SECTION 3.03.            NOTICE TO HOLDERS.

         At least 30 days but not more than 60 days before a redemption date,
the Company shall mail a notice of redemption by first-class mail to each
Holder of Securities to be redeemed at such Holder's registered address.

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

                  (1)  the redemption date;

                  (2)  the redemption price;

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

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

                  (5)  that, unless the Company defaults in the payment of the
         redemption price or accrued interest, interest on Securities called
         for redemption ceases to accrue on and after the redemption date;

                  (6)  if any Security is being redeemed in part, the portion 
         of the principal amount of such Security to be redeemed and that, 
         after the redemption date, upon surrender of such Security, a new 
         Security or Securities in principal amount equal to the unredeemed 
         portion will be issued; and

                  (7)  the subparagraph of paragraph 5 of the Securities 
         pursuant to which the Securities called for redemption are being 
redeemed.

         If any of the Securities to be redeemed is in the form of a Global
Security, then the Company shall modify such notice to the extent necessary to
accord with the procedures of DTC or its successors applicable to redemption.

         At the Company's request, the Trustee shall give the notice of
redemption in the Company's name and at the Company's expense.

SECTION 3.04.            EFFECT OF NOTICE OF REDEMPTION.

         Once notice of redemption is mailed in accordance with Section 3.03,
Securities called for redemption become due and payable on the redemption date
at the redemption price. Upon surrender to the Paying Agent, such Securities
shall be paid at the redemption price, plus accrued interest to the redemption
date. Failure to give notice or any defect in the notice to any Holder shall
not affect the validity of the notice to any Holder.


SECTION 3.05.            DEPOSIT OF REDEMPTION PRICE.

         On or before the redemption date, the Company shall deposit with the
Paying Agent immediately available funds sufficient to pay the redemption price
of, and accrued interest on, the Securities to be redeemed on that date. The
Paying Agent shall promptly return to the Company any money so deposited 



                                      -30-

<PAGE>   36
which is not required for that purpose upon the written request of the Company,
except with respect to monies owed as obligations to the Trustee pursuant to
Article Seven.

         If any Security called for redemption shall not be so paid upon
redemption because of the failure of the Company to comply with the preceding
paragraph, interest will continue to be payable on the unpaid principal,
including from the redemption date until such principal is paid, and to the
extent lawful on any interest not paid on such unpaid principal, in each case
at the rate provided in the Securities and in Section 4.01.

SECTION 3.06.            SECURITIES REDEEMED IN PART.

         Upon surrender of a Security that is to be redeemed in part, the
Company shall issue and execute and the Trustee shall authenticate for the
Holder a new Security or Securities equal in aggregate principal amount to the
unredeemed portion of the Security surrendered.

                                  ARTICLE FOUR

                                   COVENANTS

SECTION 4.01.            PAYMENT OF SECURITIES.

         The Company shall pay the principal of, and premium (if any) and
interest on, the Securities on the dates and in the manner provided in the
Securities and this Indenture. Principal of, and premium (if any) and interest
on, the Securities shall be considered paid on the date due if the Trustee or
Paying Agent holds on that date money deposited by the Company designated for
and sufficient to pay all principal, premium (if any) and interest then due.

         The Company shall pay interest on overdue principal at the rate borne
by the Securities and shall pay interest on overdue installments of interest at
the same rate to the extent lawful.

         The Company shall notify the Trustee and any Paying Agent immediately
upon the occurrence of any Registration Default and, with respect to payments
of Additional Interest, the Company shall notify the Trustee and any Paying
Agent prior to the date of any interest payment of the amount of Additional
Interest payable to each Holder.

SECTION 4.02.            SEC REPORTS.

         Each of the Company and the Subsidiary Guarantors shall file with the
Trustee within 15 days after it files them with the SEC copies of the annual
reports and of the information, documents, and other reports (or copies of such
portions of any of the foregoing as the SEC may by rules and regulations
prescribe) which each of the Company and the Subsidiary Guarantors is required
to file with the SEC pursuant to Section 13 or 15(d) of the Exchange Act. If
the Company is not subject to the requirements of such Section 13 or 15(d) of
the Exchange Act, the Company shall file on a timely basis with the SEC, to the
extent such filings are accepted by the SEC and whether or not the Company has
a class of securities registered under the Exchange Act, the annual reports,
quarterly reports and other documents that the Company would be required to
file if it were subject to Section 13 or 15 of the Exchange Act. The Company
shall also file with the Trustee (with exhibits), and provide to each Holder of
Securities or, upon request, to as prospective Holder of Securities (without
exhibits), without cost to such Holder or prospective Holder, copies of such
reports and documents within 15 days after the date on which the 




                                      -31-

<PAGE>   37
Company files such reports and documents with the SEC or the date on which the
Company would be required to file such reports and documents if the Company
were so required and, if filing such reports and documents with the SEC is not
accepted by the SEC or is prohibited under the Exchange Act, the Company shall
supply, at its cost, copies of such reports and documents (including any
exhibits thereto) to any Holder of Securities promptly upon written request.
The Company and each of the Subsidiary Guarantors also shall comply with the
other provisions of TIA ss. 314(a).

SECTION 4.03.            COMPLIANCE CERTIFICATE.

         (a) The Company shall deliver to the Trustee, within 90 days after the
end of each fiscal year of the Company, an Officers' Certificate stating that a
review of the activities of the Company and its Subsidiaries during the
preceding fiscal year has been made under the supervision of the signing
Officer or Officers, as applicable, with a view to determining whether the
Company has kept, observed, performed and fulfilled its obligations under this
Indenture, and further stating, as to each such Officer signing such
certificate, that to the best of such Officer's knowledge the Company has kept,
observed, performed and fulfilled each and every covenant contained in this
Indenture and is not in default in the performance or observance of any of the
terms, provisions and conditions hereof (or, if a Default or Event of Default
shall have occurred, describing all such Defaults or Events of Default of which
such Officer may have knowledge and what action the Company is taking or
proposes to take with respect thereto) and that to the best of such Officer's
knowledge no event has occurred and remains in existence by reason of which
payments on account of the principal of or interest, if any, on the Securities
are prohibited. Such Officers' Certificate shall comply with TIA ss. 314(a)(4).

         (b) The Company and the Subsidiary Guarantors will, so long as any of
the Securities are outstanding, deliver to the Trustee forthwith upon any
Officer becoming aware of any Default or Event of Default or default in the
performance of any covenant, agreement or condition contained in this
Indenture, an Officers' Certificate specifying such Default or Event of Default
and what action the Company or any Subsidiary Guarantor proposes to take with
respect thereto.

SECTION 4.04.            MAINTENANCE OF OFFICE OR AGENCY.

         The Company will maintain in the City of New York, an office or agency
where Securities may be surrendered for registration of transfer or exchange or
for presentation for payment and where notices and demands to or upon the
Company in respect of the Securities and this Indenture may be served. The
Company will give prompt written notice to the Trustee of the location, and any
change in the location, of such office or agency. Until otherwise designated by
the Company to the Trustee, the Company's office or agency in the City of New
York for the foregoing purposes will be the office of the Trustee maintained
for such purpose. If at any time the Company shall fail to maintain any such
required office or agency or shall fail to furnish the Trustee with the address
thereof, such presentations, surrenders, notices and demands may be made or
served at the address of the Trustee set forth in Section 11.02.

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



                                      -32-

<PAGE>   38
SECTION 4.05.            CORPORATE EXISTENCE.

         Subject to Article Five, the Company will do or cause to be done all
things necessary to preserve and keep in full force and effect its corporate
existence and the corporate, partnership or other existence of each Material
Subsidiary in accordance with the respective organizational documents of the
Company and each Material Subsidiary and the material rights (charter and
statutory) and material franchises of the Company and the Material
Subsidiaries; provided, that the Company shall not be required to preserve any
such right or franchise, or the corporate existence of any Material Subsidiary,
if the Board of Directors of the Company shall determine that the preservation
thereof is no longer desirable in the conduct of the business of the Company
and that the loss thereof is not, and will not be, adverse to the payment and
performance of the obligations under the Securities and otherwise under this
Indenture.

SECTION 4.06.            WAIVER OF STAY, EXTENSION OR USURY LAWS.

         The Company and each Subsidiary Guarantor covenants (to the extent
that each may lawfully do so) that it will not at any time insist upon, plead,
or in any manner whatsoever claim or take the benefit or advantage of, any
stay, extension, or usury law or other law, which would prohibit or forgive the
Company or any Subsidiary Guarantor from paying all or any portion of the
principal of and/or interest on the Securities as contemplated herein, wherever
enacted, now or at any time hereafter in force, or which may affect the
covenants or the performance of this Indenture; and (to the extent that it may
lawfully do so) the Company and each Subsidiary Guarantor hereby expressly
waives all benefit or advantage of any such law, and covenants that it will not
hinder, delay or impede the execution of any power herein granted to the
Trustee, but will suffer and permit the execution of every such power as though
no such law had been enacted.

SECTION 4.07.            PAYMENT OF TAXES AND OTHER CLAIMS.

         The Company and each Material Subsidiary 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 Material Subsidiary or upon the income, profits or property of
the Company or any Material Subsidiary other than any such tax, assessment,
charge or claim whose amount, applicability or validity is being contested in
good faith by appropriate proceedings and for which appropriate provision has
been made in accordance with GAAP, and (2) all lawful claims for labor,
materials and supplies which, if unpaid, might by law become a Lien (other than
a Permitted Lien) upon the property of the Company or any Material Subsidiary,
in each case except to the extent the failure to do so would have, in the
judgment of the Company, a material adverse effect on the Company and the
Subsidiaries taken as a whole.

SECTION 4.08.            MAINTENANCE OF PROPERTIES AND INSURANCE.

         (a) The Company shall cause all material Property 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 (ordinary wear and tear
excepted) and supplied with all necessary equipment and shall 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 shall
prevent the Company or any Subsidiary from discontinuing the operation or
maintenance of any such Property, or disposing of it, if such discontinuance or
disposal is, in the 




                                      -33-

<PAGE>   39
judgment of the Company or such Subsidiary, desirable in the conduct of its
business and not adverse to the payment and performance of the obligations
under the Securities and otherwise under this Indenture.

         (b) The Company shall provide or cause to be provided, for itself and
each of its Subsidiaries, insurance (including appropriate self-insurance)
against loss or damage of the kinds that, in the reasonable, good faith opinion
of the Company are adequate and appropriate for the conduct of the business of
the Company and such Subsidiaries in a prudent manner, with reputable insurers
or with the government of the United States or an agency or instrumentality
thereof, in such amounts, with such deductibles, and by such methods as shall
be either (i) consistent with past practices of the Company or the applicable
Subsidiary or (ii) customary, in the reasonable, good faith opinion of the
Company, for corporations similarly situated in the industry, unless the
failure to provide such insurance (together with all other such failures) would
not have a material adverse effect on the financial condition or results of
operations of the Company and its Subsidiaries, taken as a whole.

SECTION 4.09.            LIMITATION ON INCURRENCE OF ADDITIONAL INDEBTEDNESS.

         The Company will not, and will not permit any of the Subsidiaries to
directly or indirectly, issue, incur, assume, guarantee, become liable,
contingently or otherwise, with respect to or otherwise become responsible for
the payment of (collectively, "incur") any Indebtedness (other than Permitted
Indebtedness); provided, however, that if no Default or Event of Default with
respect to the Securities shall have occurred and be continuing at the time or
as a consequence at the incurrence of such Indebtedness, the Company may incur
Indebtedness and any Subsidiary may incur Indebtedness, if on the date of the
incurrence, the Company's Consolidated EBITDA Coverage Ratio would have been
greater than 2.0 to 1.0.

         For purposes of determining any particular amount of Indebtedness
incurred under this Section 4.09, (i) guarantees by the Company or any of the
Subsidiaries of Indebtedness of the Company or any of the Subsidiaries
otherwise included in the determination of such amount shall not also be
included, and (ii) any Indebtedness of the Company or any Subsidiary incurred
for, or related to, a Person other than another Subsidiary or the Company, as
applicable, shall be deemed to be in an amount equal to the greater of (a) the
lesser of (1) the full amount of the Indebtedness of such other Person or (2)
the fair market value of the assets and properties of the Company or such
Subsidiary, as to which the holder or holders of such Indebtedness are
expressly limiting the obligations of the Company or such Subsidiary, the value
of which assets and properties of the Company or any Subsidiary will be
determined in good faith by the Board of Directors of the Company or such
Subsidiary, as applicable (which determination shall be evidenced by a Board
Resolution of the applicable Person), and (b) the amount of the Indebtedness of
such other Person as has been expressly contractually assumed or guaranteed by
the Company or such Subsidiary.

         Notwithstanding anything to the contrary in this Section 4.09, no
Subsidiary that is not already a Subsidiary Guarantor shall incur any
Indebtedness with respect to any Indebtedness of the Company or any other
Subsidiary unless such Subsidiary, the Company and the Trustee execute and
deliver a supplemental indenture evidencing such Subsidiary Guarantor's
Subsidiary Guarantee of the Securities, such Subsidiary Guarantee to be a
senior unsecured obligation of such Subsidiary.



                                      -34-

<PAGE>   40
SECTION 4.10.            LIMITATION ON SUBORDINATED INDEBTEDNESS.

         Neither the Company nor any Subsidiary Guarantor may, directly or
indirectly, in any event incur any Indebtedness that by its terms (or by the
terms of any agreement governing such Indebtedness) is subordinated to any
other Indebtedness of the Company or such Subsidiary Guarantor, as the case may
be, unless such Indebtedness is also by its terms (or by the terms of any
agreement governing such Indebtedness) made expressly subordinate to the
Securities or the Subsidiary Guarantee of such Subsidiary Guarantor, as the
case may be, to the same extent and in the same manner as such Indebtedness is
subordinated pursuant to subordination provisions that are most favorable to
the holders of any other Indebtedness of the Company or such Subsidiary
Guarantor, as the case may be.

SECTION 4.11.            LIMITATION ON RESTRICTED PAYMENTS.

         The Company will not, and will not permit any of the Subsidiaries to,
directly or indirectly, make any Restricted Payment, if at the time of such
Restricted Payment, or on a pro forma basis after giving effect thereto:

                  (x)    a Default or an Event of Default under this 
         Indenture has occurred and is continuing;

                  (y)    the aggregate amount expended for all Restricted 
         Payments subsequent to the Issue Date exceeds the sum of (without 
         duplication):

                         (1)  50% of aggregate Consolidated Net Income of the
                  Company (or if such Consolidated Net Income is a loss, minus
                  100% of such loss) earned on a cumulative basis during the
                  period beginning on the first day of the month containing the
                  Issue Date and ending on the last date of the Company's
                  fiscal quarter immediately preceding such Restricted Payment;
                  plus

                         (2)  100% of the aggregate Net Proceeds received by
                  the Company from any Person other than a Subsidiary from the
                  issuance and sale subsequent to the Issue Date of Qualified
                  Capital Stock (excluding (A) any Qualified Capital Stock paid
                  as a dividend on any Capital Stock or as interest on any
                  Indebtedness, (B) the issuance of Qualified Capital Stock
                  upon the conversion of, or in exchange for, any Qualified
                  Capital Stock and (C) any Qualified Capital Stock with regard
                  to issuances and sales financed directly or indirectly using
                  funds borrowed from the Company or any Subsidiary, until and
                  to the extent such borrowing is repaid); plus

                         (3)  to the extent not otherwise included in
                  Consolidated Net Income, dividends, repayments of loans or 
                  advances, or other transfers of assets, in each case to the
                  Company or a Subsidiary after the date of this Indenture from
                  any Unrestricted Subsidiary or from the redesignation of an
                  Unrestricted Subsidiary as a Subsidiary (valued in each case
                  as provided in the definition of Investment) other than
                  amounts constituting Permitted Unrestricted Subsidiary
                  Investments; and

                         (4)  $5.0 million; or

                  (z)  the Company would not be able to incur $1.00 of
         additional Indebtedness (excluding Permitted Indebtedness) as provided
         in the first paragraph of Section 4.09.




                                      -35-

<PAGE>   41
         The foregoing provisions of this covenant will not prevent the payment
of any dividend within 60 days after the date of its declaration if the
dividend would have been permitted on the date of declaration; provided,
however, that payments made in accordance with this paragraph shall be counted
for purposes of computing amounts expended pursuant to subclause (y) in the
immediately preceding paragraph.

SECTION 4.12.            LIMITATION ON ASSETS SALES.

         The Company may not, and may not permit any of its Subsidiaries to,
engage in an Asset Sale unless:

                  (i) the Company (or the Subsidiary, as the case may be)
         receives consideration at the time of such Asset Sale at least equal
         to the fair market value (evidenced by a resolution of the Board of
         Directors set forth in an Officers' Certificate delivered to the
         Trustee for an Asset Sale or series of related Asset Sales involving
         assets of the Company or its Subsidiaries having an aggregate value of
         more than $5.0 million) of the assets or Capital Stock issued or sold
         or otherwise disposed of and

                  (ii) the consideration therefor received by the Company or
         such Subsidiary is in the form of cash and Cash Equivalents or
         Permitted Industry Investments;

provided that the amount of any liabilities (as shown on the Company's or such
Subsidiary's most recent balance sheet) of the Company or any Subsidiary (other
than contingent liabilities and liabilities that are by their terms
subordinated to the Securities or the Subsidiary Guarantees) that are assumed
by the transferee of any such assets pursuant to a customary novation agreement
that releases the Company or such Subsidiary from further liability shall be
deemed to be cash for purposes of this provision (but shall not be deemed to be
"Excess Proceeds" as defined below); and provided further, that the Company or
such Subsidiary may accept proceeds from such Asset Sale in other than cash and
Cash Equivalents or Permitted Industry Investments or any combination of the
foregoing if the aggregate amount of all proceeds from all Asset Sales after
the Issue Date that are other than cash, Cash Equivalents or Permitted Industry
Investments after such Asset Sale, does not exceed 15% of Consolidated Net
Tangible Assets at the date of such Asset Sale.

         Within 365 days after the receipt of any Net Available Proceeds from
any Asset Sale, the Company (or the Subsidiary, as the case may be) may:

                  (i) apply all or any part of the Net Available Proceeds
         therefrom to repay Senior Indebtedness of the Company or Guarantor
         Senior Indebtedness of a Subsidiary Guarantor or

                  (ii) invest all or any part of the Net Available Proceeds
         thereof in Permitted Industry Investments made by the Company or a
         Subsidiary or, to the extent not so applied during such 365-day
         period, to such investments specifically identified during such
         365-day period reasonably anticipated in good faith by the Board of
         Directors of the Company to be expended within 180 days after being
         specifically identified (such 180-day period, the "Project Period").

Pending the final application of any such Net Available Proceeds, the Company
may temporarily reduce borrowings under any revolving credit facility or
otherwise invest such Net Available Proceeds in any manner that is not
prohibited by this Indenture. Any Net Available Proceeds from Asset Sales
occurring on or after the Issue Date that are not applied or invested within
365 days of the receipt thereof (or if 



                                      -36-

<PAGE>   42
later, within 35 Business Days following an applicable Project Period) as
provided in the first sentence of this paragraph will be deemed to constitute
"Excess Proceeds". When the aggregate amount of Excess Proceeds equals or
exceeds $10.0 million (the date of such occurrence, the "Asset Sale Offer
Trigger Date"), the Company shall make an offer to all Holders of Securities
(an "Asset Sale Offer") to purchase the maximum principal amount of Securities
that may be purchased out of such Excess Proceeds, at an offer price in cash in
an amount equal to 100% of the principal amount thereof, plus accrued and
unpaid interest thereon to the date of purchase in accordance with the
procedures set forth below in this Section 4.12 and Additional Interest (if
any) as set forth in the Registration Rights Agreement. To the extent that the
aggregate amount of Securities tendered pursuant to an Asset Sale Offer is less
than the applicable Excess Proceeds, the Company may use any of such remaining
Excess Proceeds for general corporate purposes. Upon completion of such Asset
Sale Offer, the amount of Excess Proceeds shall be reset at zero.

         The Company will not enter into or suffer to exist or permit any
Subsidiary to enter into or suffer to exist any agreement that would place any
restriction of any kind (other than pursuant to law or regulation) on the
ability of the Company to make an Asset Sale Offer following any Asset Sale.

         In the event that, pursuant to this Section 4.12, the Company shall be
required to commence an Asset Sale Offer, it shall follow the procedures
specified below.

                  (a) The Asset Sale Offer shall be made to all Holders and
         shall remain open for a period of at least 20 Business Days following
         its commencement (the "Offer Period").

                  (b) If the Asset Sale Offer Purchase Date is on or after an
         interest record date and on or before the related interest payment
         date, any accrued and unpaid interest thereon, if any (including, if
         any, Additional Interest), shall be paid to the Person in whose name a
         Security is registered at the close of business on such record date,
         and no additional interest shall be payable to Holders who tender
         Securities pursuant to the Asset Sale Offer.

                  (c) Within 10 Business Days following any Asset Sale Offer
         Trigger Date, the Company shall send, by first class mail, a notice to
         each of the Holders at such Holder's registered address, with a copy
         to the Trustee. The notice, which shall govern the terms of the Asset
         Sale Offer, shall contain all instructions and materials necessary to
         enable such Holders to tender Securities pursuant to the Asset Sale
         Offer, and shall state:

                           (1) (A) that the Asset Sale Offer Trigger Date has
                  occurred pursuant to Section 4.12, and that the Company is
                  offering to purchase the maximum principal amount of
                  Securities that may be purchased out of the Excess Proceeds
                  (the "Offer Amount") at an offer price in cash in an amount
                  equal to 100% of the principal amount thereof, plus accrued
                  and unpaid interest thereon, if any (including, if any,
                  Additional Interest), to the date of purchase, which shall be
                  a Business Day (the "Asset Sale Offer Purchase Date") that is
                  not earlier than 30 Business Days nor later than 60 Business
                  Days from the date such notice is mailed, unless otherwise
                  required by applicable law and (B) the amount of the Offer
                  Amount and the date of the Asset Sale Offer Purchase Date;

                           (2) the amount of accrued and unpaid interest, 
                  if any (including, if any, Additional Interest), as of the 
                  Asset Sale Offer Purchase Date;



                                     -37-

<PAGE>   43
                           (3) that any Securities or portions thereof 
                  subject to the Asset Sale Offer not tendered or accepted for 
                  payment shall continue to accrue interest;

                           (4) that, unless the Company defaults in the payment
                  of the purchase price for the Securities payable pursuant to
                  the Asset Sale Offer, any such Securities or portions thereof
                  accepted for payment pursuant to the Asset Sale Offer shall
                  cease to accrue interest after the Asset Sale Offer Purchase
                  Date;

                           (5) that Holders electing to have any Securities or
                  portions thereof purchased pursuant to any Asset Sale Offer
                  shall be required to surrender such Securities, duly endorsed
                  for transfer with the form entitled "Option of Holder to
                  Elect Purchase" on the reverse of such Securities completed,
                  to the Company or a Paying Agent at the address specified in
                  the notice at least 3 Business Days before the Asset Sale
                  Offer Purchase Date;

                           (6) that Holders shall be entitled to withdraw their 
                  election if the Company or the Paying Agent, as the case may 
                  be, receives, before the expiration of the Offer Period, a 
                  facsimile transmission or letter setting forth the name of 
                  the Holder, the principal amount of the Securities the Holder 
                  delivered for purchase and a statement that such Holder is 
                  withdrawing its election to have such Securities or portions 
                  thereof purchased;

                           (7) that, if (A) the aggregate principal amount of
                  Securities surrendered by Holders exceeds the Offer Amount or
                  (B) less than all of the Securities tendered pursuant to the
                  Asset Sale Offer are accepted for payment by the Company for
                  any reason consistent with this Indenture, the Trustee shall
                  select the Securities to be purchased in compliance with the
                  requirements of the principal national securities exchange,
                  if any, on which the Securities are listed or, if the
                  Securities are not so listed, on a pro rata basis, by lot or
                  by such method as the Trustee deems fair and appropriate;
                  provided that Securities accepted for payment in part will
                  only be purchased in integral multiples of $1,000; and

                           (8) that Holders whose Securities were purchased
                  only in part shall be issued new Securities equal in
                  principal amount to the unpurchased portion of the Securities
                  surrendered.

                  (d) If any of the Securities subject to an Asset Sale Offer
         is held of record by DTC, then (x) the Company shall modify such
         notice to the extent necessary to accord with the procedures of DTC
         applicable to repurchases, (y) the Company or its designated agent may
         accept as tendered for repurchase pursuant to this Section 4.12
         Securities tendered by means of book entry in accordance with normal
         procedures of DTC and (z) the Trustee will return to the Holder of a
         Global Security that is being purchased in part, such Global Security
         with a notation duly noted on it adjusting the principal amount
         thereof to be equal to the unpurchased portion of such Global
         Security.

                  (e) On the Asset Sale Offer Purchase Date, the Company shall:
         (i) accept for payment the maximum principal amount of Securities or
         portions thereof tendered pursuant to the Asset Sale Offer that can be
         purchased out of the Excess Proceeds, (ii) deposit with the Paying
         Agent the aggregate purchase price of all Securities or portions
         thereof accepted for payment and 



                                      -38-

<PAGE>   44
         (iii) deliver or cause to be delivered to the Trustee all Securities
         tendered pursuant to the Asset Sale Offer. The Company or the Paying
         Agent, as the case may be, shall promptly mail to each Holder of
         Securities or portions thereof accepted for payment an amount equal to
         the purchase price for such Securities, and the Company will execute
         and the Trustee shall promptly authenticate and mail to any such
         Holder of Securities accepted for payment in part a new Security equal
         in principal amount to any unpurchased portion of the Securities, and
         any Security not accepted for payment in whole or in part shall be
         promptly returned to the Holder of such Security. The Company shall
         announce the results of the Asset Sale Offer to Holders of the
         Securities on or as soon as practicable after the Asset Sale Offer
         Purchase Date. The Company shall comply with the requirements of Rule
         14e-1 under the Exchange Act, and any other securities laws or
         regulations thereunder, if applicable, in connection with any Asset
         Sale Offer.

SECTION 4.13.            LIMITATION ON LIENS SECURING INDEBTEDNESS.

         The Company will not, and will not permit any of the Subsidiaries to,
create, incur, assume or suffer to exist any Liens (other than Permitted Liens)
upon any of their respective Properties securing (i) any Indebtedness of the
Company, unless the Securities are equally and ratably secured or (ii) any
Indebtedness of any Subsidiary Guarantor, unless the Securities or the
Subsidiary Guarantees, as the case may be, are equally and ratably secured;
provided that if such Indebtedness is expressly subordinated to the Securities
or the Subsidiary Guarantees, the Lien securing such Indebtedness will be
subordinated and junior to the Lien securing the Securities or the Subsidiary
Guarantees, with the same relative priority as such subordinated Indebtedness
will have with respect to the Securities or the Subsidiary Guarantees, as the
case may be.

SECTION 4.14.         LIMITATION ON PAYMENT RESTRICTIONS AFFECTING SUBSIDIARIES.

         The Company will not, and will not permit any Subsidiary to, directly
or indirectly, create or suffer to exist or allow to become effective any
consensual encumbrance or restriction of any kind (i) on the ability of any of
the Subsidiaries (a) to pay dividends or make other distributions on its
Capital Stock or make payments on any Indebtedness owed to the Company or any
other Subsidiary, (b) to make loans or advances to the Company or any other
Subsidiary, or (c) to transfer any of its Property to the Company or any other
Subsidiary, or (ii) on the ability of such Person or any other subsidiary of
such Person to receive or retain any such (a) dividends, distributions or
payments, (b) loans or advances, or (c) transfers of Property (any such
restriction being referred to herein as a "Payment Restriction"), except for
such encumbrances or restrictions existing under or by reason of (1) the Credit
Facility as in effect from time to time, (2) customary provisions restricting
subletting or assignment of any lease governing a leasehold interest of the
Company or any Subsidiary, (3) any instrument governing Indebtedness of a
Person acquired by the Company or a Subsidiary at the time of such acquisition,
which encumbrance or restriction is not applicable to any Person, other than
the Person, or the Property of the Person, so acquired, provided that such
Indebtedness was not incurred in anticipation of such acquisition, (4) with
respect to clauses (i)(c) and (ii)(c) above, Purchase Money Obligations for
Property acquired in the ordinary course of business, (5) Indebtedness existing
pursuant to a written agreement in effect on the date of this Indenture, (6)
Indebtedness under this Indenture, or (7) Indebtedness incurred to refinance,
refund, extend or renew Indebtedness referred to in clauses (1), (3), (4) or
(5) above; provided that the Payment Restrictions contained therein are not
materially more restrictive than those provided for in the Indebtedness being
refinanced, refunded, extended or renewed.



                                      -39-

<PAGE>   45
SECTION 4.15.            LIMITATION ON TRANSACTIONS WITH RELATED PERSONS.

         Neither the Company nor any of the Subsidiaries will (i) sell, lease,
transfer or otherwise dispose of any of its Property to, (ii) purchase any
property from, (iii) make any Investment (other than Permitted Unrestricted
Subsidiary Investments and other Investments that do not breach the provisions
of Section 4.11) in, or (iv) enter into any contract or agreement with or for
the benefit of, a Related Person of the Company or any Subsidiary (other than
the Company or any such Subsidiary in which no Related Person (other than the
Company or another Wholly Owned Subsidiary) owns, directly or indirectly, an
equity interest) (a "Related Party Transaction"), unless (a) such Related Party
Transaction or series of associated Related Party Transactions is on terms that
are no less favorable to the Company or such Subsidiary, as the case may be,
than those that could be obtained in a comparable arm's length transaction with
an unrelated third party, (b) with respect to any Related Party Transaction or
series of associated Related Party Transactions involving aggregate payments in
excess of $1.0 million, the Company delivers, within 30 days of such Related
Party Transaction or series of associated Related Party Transactions, an
Officers' Certificate to the Trustee certifying that such Related Party
Transaction or series of associated Related Party Transactions complies with
the immediately preceding clause (a), and (c) with respect to a Related Party
Transaction or series of associated Related Party Transactions involving
payments of $5.0 million or more, the Company delivers, within 30 days of such
Related Party Transaction or series of associated Related Party Transactions,
an Officers' Certificate to the Trustee certifying that (1) such Related Party
Transaction or series of associated Related Party Transactions complies with
clause (a) above and (2) such Related Party Transaction or series of associated
Related Party Transactions has been approved by a majority of the independent
directors of the Company. Notwithstanding anything to the contrary in the
foregoing, the foregoing restrictions shall not apply to (A) Related Party
Transactions that are approved by the Board of Directors of the Company and
such Subsidiary, if applicable, as in the best interests of the Company or such
Subsidiary, which transactions together with all other Related Party
Transactions in a related series involve or have an aggregate value not
exceeding $1.0 million in each fiscal year, (B) fees and compensation paid to
or agreements with officers, directors, employees or consultants of the Company
or any Subsidiary, in each case that are reasonable, as determined by the Board
of Directors or senior management thereof in good faith; (C) Employee Stock
Repurchases, (D) transactions described under the heading "Certain
Relationships and Related Transactions" in the Offering Circular of the Company
dated August 14, 1997, relating to the issuance of the Securities, and (E)
Restricted Payments that are not prohibited by the provision of Section 4.11.

SECTION 4.16.            LIMITATION ON CONDUCT OF BUSINESS.

         The Company and the Subsidiaries will be operated in a manner such
that their business activities will be in the oilfield services business and
related products and services, including, but not limited to, (i) rental of
downhole tools, general oil field equipment, petrochemical equipment and
industrial and other equipment (which may include equipment not used in the oil
and gas industry), (ii) drilling services, (iii) pipeline testing services, and
(iv) such other businesses as are reasonably necessary or desirable to
facilitate the conduct and operations of the foregoing businesses.

SECTION 4.17.            CHANGE OF CONTROL.

         (a) Upon the occurrence of a Change of Control, the Company shall make
an offer to purchase all of the then outstanding Securities (a "Change of
Control Offer") from the Holders of such Securities, at a purchase price (the
"Change of Control Purchase Price") in cash equal to 101% of the aggregate
principal amount of such Securities, plus accrued and unpaid interest, if any,
to the Change 



                                      -40-

<PAGE>   46
of Control Purchase Date (as defined below), in accordance with the procedures
set forth in paragraphs (b), (c) and (d) of this Section. The Company shall,
subject to the provisions described below, be required to purchase all
Securities properly tendered pursuant to a Change of Control Offer and not
withdrawn.

         (b) The Change of Control Offer shall remain open for at least 20
Business Days and until the close of business on the fifth Business Day prior
to the Change of Control Purchase Date (as defined below) and in any event, for
such period as required by applicable law.

         (c) Not later than the 30th day following the occurrence of a Change
of Control, the Company shall mail to the Trustee and to each Holder of the
Securities a notice (the "Change of Control Notice") stating:

                  (1) that a Change in Control has occurred and that such
         Holder has the right to require the Company to repurchase such
         Holder's Securities, or portion thereof, at the Change of Control
         Purchase Price;

                  (2) any information regarding such Change of Control required
         to be furnished pursuant to Section 14(e) of the Exchange Act and any
         other applicable securities laws and regulations thereunder;

                  (3) a purchase date (the "Change of Control Purchase Date")
         which shall be on a Business Day and no earlier than 30 days nor later
         than 60 days after the occurrence of the Change of Control;

                  (4) that any Security, or portion thereof, not tendered or 
         accepted for payment will continue to accrue interest;

                  (5) that unless the Company defaults in making payments
         therefor, or payment is otherwise prevented, any Security, or portion
         thereof, accepted for payment pursuant to the Change of Control Offer
         shall cease to accrue interest after the Change of Control Purchase
         Date; and

                  (6) the instructions a Holder must follow in order to have
         his Securities repurchased in accordance with paragraph (d) of this
         Section 4.17.

         No failure of the Company to give the foregoing notice shall limit any
Holder's right to exercise a repurchase right.

         (d) To exercise the repurchase right, the Holder must deliver, on or
before the fifth calendar day prior to the Change of Control Purchase Date,
written notice to the Company (or an agent designated by the Company for such
purpose) of the Holder's exercise of such right, together with (i) the Security
or Securities with respect to which the right is being exercised, duly endorsed
for transfer with the form entitled "Option of Holder to Elect Purchase" on the
reverse of the Security completed, and (ii) if the Change of Control Purchase
Date falls between any record date for the payment of interest on the
Securities and the next succeeding interest payment date, an amount equal to
the interest which the Holder is entitled to receive on such interest payment
date; provided, however, that with respect to Securities held of record by DTC,
(y) the Company shall modify such notice to the extent necessary to accord with
the procedures of DTC applicable to repurchases, and (z) the Company or its
designated agent may accept 



                                      -41-

<PAGE>   47
as tendered for repurchase pursuant to this Section 4.17 Securities tendered by
means of a book entry in accordance with the normal procedures of DTC, provided
that any such interest amount shall be delivered by the Holder to the Company
or its designated agent. Notwithstanding the foregoing, if prior to the date
that a Change of Control Notice is required to be mailed, a notice of optional
redemption of all of the outstanding Securities has been mailed in accordance
with the terms of this Indenture, the Company's obligation to send the Change
of Control Notice shall be suspended (unless the Company shall default in the
payment of the redemption price or accrued interest).

         (e) On the Change of Control Purchase Date, the Company shall (i)
accept for payment Securities or portions thereof tendered pursuant to the
Change of Control Notice, (ii) if the Company appoints a depository or Paying
Agent, deposit with such depository or Paying Agent money sufficient to pay the
purchase price of all Securities or portions thereof so tendered and (iii)
deliver to the Trustee Securities so accepted together with an Officers'
Certificate stating the Securities or portions thereof tendered to the Company.
DTC, the Company or the Paying Agent, as the case may be, shall promptly mail
to the Holder of Securities so accepted payment in an amount equal to the
purchase price, and the Trustee shall promptly authenticate and mail to such
Holders of Physical Securities a new Security equal in principal amount to any
unpurchased portion of the Security surrendered. The Company will publicly
announce the results of the Change of Control Offer on or as soon as
practicable after the Change of Control Purchase Date. For purposes of this
Section 4.17, the Trustee shall act as the Paying Agent.

         (f) The Company, to the extent applicable and if required by law, will
comply with Sections 13 and 14 of the Exchange Act and the provisions of
Regulation 14E and any other tender offer rules under the Exchange Act and any
other federal and state securities laws, rules and regulations which may then
be applicable to any offer by the Company to purchase the Securities pursuant
to the provisions of this Section 4.17.

SECTION 4.18.            SALE-AND-LEASEBACK TRANSACTIONS.

         The Company will not, and will not permit any Subsidiaries to, enter
into any sale-and-leaseback transaction; provided that the Company or any
Subsidiary, as applicable, may enter into a sale-and-leaseback transaction if
(i) the Company could have (a) incurred Indebtedness in an amount equal to the
Attributable Indebtedness relating to such sale-and- leaseback transaction
pursuant to the Consolidated EBITDA Coverage Ratio test set forth in the first
paragraph of Section 4.09 and (b) created a Lien to secure such Indebtedness
pursuant to Section 4.13, (ii) the fair market value of the consideration of
such sale-and-leaseback transaction is at least equal to the fair market value
(as determined in good faith by the Board of Directors and set forth in an
Officers' Certificate delivered to the Trustee) of the Property that is the
subject of such sale-and-leaseback transaction, and (iii) the transfer of
assets in such sale-and-leaseback transaction is permitted by, and the Company
applies the proceeds of such transaction in compliance with, Section 4.12.

SECTION 4.19.            ISSUANCES AND SALES OF CAPITAL STOCK OF WHOLLY OWNED 
                         SUBSIDIARIES.

         The Company (i) may not, and may not permit any Wholly Owned
Subsidiary to, transfer, convey, sell or otherwise dispose of any Capital Stock
of any Wholly Owned Subsidiary to any Person (other than the Company or a
Wholly Owned Subsidiary), unless (a) such transfer, conveyance, sale or other
disposition is of all the Capital Stock of such Wholly Owned Subsidiary and (b)
the cash Net Available Proceeds from such transfer, conveyance, sale or other
disposition are applied in accordance with Section 4.12, and (ii) may not
permit any Wholly Owned Subsidiary of the Company to issue any of its Capital
Stock or any warrants, options or other rights to acquire Capital Stock (but
excluding any 



                                      -42-

<PAGE>   48
debt security that is convertible into, or exchangeable for,
Capital Stock) to any Person other than to the Company or a Wholly Owned
Subsidiary; except, in the case of both clauses (i) and (ii) in this Section
4.19, with respect to dispositions or issuances by a Wholly Owned Subsidiary of
the Company as contemplated in clauses (i) and (ii) of the definition of
"Wholly Owned Subsidiary".

SECTION 4.20.            REGISTRATION RIGHTS AGREEMENT.

         The Company will comply with all of the terms and provisions of the
Registration Rights Agreement, including, without limitation, its obligation to
pay Additional Interest (as defined therein) and to notify the Trustee
immediately of the occurrence of any Registration Default (as defined therein)
thereunder.

SECTION 4.21.            QUALIFICATION OF INDENTURE.

         The Company shall qualify this Indenture under the TIA in accordance
with the terms and conditions of the Registration Rights Agreement and shall
pay all costs and expenses (including attorneys' fees for the Company and the
Trustee) incurred in connection therewith. In connection with any such
qualification of this Indenture under the TIA, the Trustee shall be entitled to
receive from the Company any such Officers' Certificates, Opinions of Counsel
or other documentation as it may reasonably request.

                                  ARTICLE FIVE

                             SUCCESSOR CORPORATION

SECTION 5.01.            WHEN COMPANY MAY MERGE, ETC.

         The Company shall not consolidate with or merge with any Person or
convey, transfer or lease all or substantially all of its Property to any
Person, unless:

                  (1)  the Company survives such merger or the Person formed by
         such consolidation or into which the Company is merged or that
         acquires by conveyance or transfer, or which leases, all or
         substantially all of the Property of the Company is a corporation
         organized and existing under the laws of the United States of America,
         any State thereof or the District of Columbia and expressly assumes,
         by supplemental indenture, the due and punctual payment of the
         principal of, and premium, if any, and interest on all the Securities
         and the performance of every other covenant and obligation of the
         Company under this Indenture;

                  (2)  immediately before and after giving effect to such 
         transaction no Default or Event of Default exists;

                  (3)  immediately after giving effect to such transaction on 
         a pro forma basis, the Consolidated Net Worth of the Company (or, if 
         not the Company, the surviving or transferee entity) is equal to or 
         greater than the Consolidated Net Worth of the Company immediately 
         before such transaction; and

                  (4)  immediately after giving effect to such transaction on a
         pro forma basis, the Company (or, if not the Company, the surviving or
         transferee entity) would be able to incur $1.00 of additional
         Indebtedness (excluding Permitted Indebtedness) under the test
         described in the first paragraph of Section 4.09.



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<PAGE>   49
         The Company shall deliver to the Trustee prior to the consummation of
the proposed transaction an Officers' Certificate to the foregoing effect and
an Opinion of Counsel stating that the proposed transaction and such
supplemental indenture comply with this Indenture.

SECTION 5.02.            SUCCESSOR CORPORATION SUBSTITUTED.

         Upon any consolidation, merger, conveyance, lease or transfer in
accordance with Section 5.01, the successor Person formed by such consolidation
or into which the Company is merged or to which such conveyance, lease or
transfer is made shall succeed to, and be substituted for, and may exercise
every right and power of, the Company under this Indenture with the same effect
as if such successor had been named as the Company herein, and thereafter
(except in the case of a lease) the predecessor corporation will be relieved of
all further obligations and covenants under this Indenture and the Securities.

                                  ARTICLE SIX

                             DEFAULTS AND REMEDIES

SECTION 6.01.            EVENTS OF DEFAULT.

         An "Event of Default" occurs upon:

                  (1) default in the payment of principal of, or premium, if
         any, on the Securities when due at maturity, upon repurchase, upon
         acceleration or otherwise, including failure of the Company to
         repurchase the Securities required to be repurchased, at the required
         purchase price, upon a Change of Control or an Asset Sale Offer, and
         failure to make, when due, any optional redemption payment;

                  (2) default in the payment of any installment of interest on
         the Securities when due (including any interest payable in connection
         with optional redemption payments) and continuance of such default for
         30 days;

                  (3) default on any other Indebtedness of the Company, any
         Subsidiary Guarantor or any other Subsidiary if either (a) such
         default results from the failure to pay principal of, premium, if any,
         or interest on, any such Indebtedness when due in excess of $5.0
         million and continuance of such default beyond any applicable cure,
         forbearance or notice period, or (b) as a result of such default, the
         maturity of such Indebtedness has been accelerated prior to its
         scheduled maturity, without such default and acceleration having been
         rescinded or annulled within a period of 10 days, and the principal
         amount of such Indebtedness, together with the principal amount of any
         other such Indebtedness in default, or the maturity of which has been 
         so accelerated, aggregates $5.0 million or more;

                  (4) default in the performance, or breach, of any other
         covenant of the Company or any Subsidiary Guarantor in this Indenture
         and failure to remedy such default within a period of 45 days after
         written notice thereof from the Trustee or Holders of 25% in principal
         amount of the outstanding Securities;

                  (5) the entry by a court of one or more judgments or orders
         against the Company, any Subsidiary Guarantor or any other Subsidiary
         in an aggregate amount in excess of 




                                      -44-
<PAGE>   50
         $5.0 million and which are not covered by insurance written by third 
         parties that has not been vacated, discharged, satisfied or stayed 
         pending appeal within 60 days from the entry thereof;

                  (6)  a Subsidiary Guarantee by a Subsidiary Guarantor that is
         a Material Subsidiary shall cease to be in full force and effect
         (other than a release of a Subsidiary Guarantee by designation of such
         Subsidiary Guarantor as an Unrestricted Subsidiary or as otherwise
         provided under this Indenture in connection with the sale, liquidation
         or other transfer of such Subsidiary Guarantor) or any Subsidiary
         Guarantor shall deny, disaffirm or seek to revoke its obligations with
         respect thereto;

                  (7)  the Company or any Material Subsidiary pursuant to or 
         within the meaning of any Bankruptcy Law:

                           (A)   commences a voluntary case or proceeding,

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

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

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

                           (E)   admits in writing that it generally is unable 
                  to pay its debts as the same become due; or

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

                           (A)  is for relief (with respect to the petition
                  commencing such case) against the Company or any Material
                  Subsidiary in an involuntary case or proceeding,

                           (B)  appoints a Custodian of the Company or any 
                  Material Subsidiary or for all or substantially all of its 
                  respective Property, or

                           (C)  orders the liquidation of the Company or any
                  Material Subsidiary, and the order or decree remains
                  unstayed and in effect for 60 days.

         The term "Bankruptcy Law" means Title 11, U.S. Code or any similar
federal or state law for the relief of debtors. The term "Custodian" means any
receiver, trustee, assignee, liquidator or similar official under any
Bankruptcy Law.

SECTION 6.02.            ACCELERATION.

         If an Event of Default (other than an Event of Default specified in
clauses (7) and (8) of Section 6.01) under Section 6.01 occurs and is
continuing, then and in every such case the Trustee or the Holders of not less
than 25% in principal amount of the outstanding Securities may declare the
unpaid principal of (or the Change of Control Purchase Price if the Event of
Default includes failure to pay the Change of Control Purchase Price), and
accrued and unpaid interest on, all the Securities then outstanding



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<PAGE>   51
to be due and payable, by a notice in writing to the Company (and to the
Trustee, if given by Holders) and upon any such declaration such principal
amount, premium, if any, and accrued and unpaid interest shall become
immediately due and payable, notwithstanding anything contained in this
Indenture or the Securities to the contrary. If an Event of Default specified
in clauses (7) or (8) of Section 6.01 occurs, all unpaid principal of, and
accrued interest on, the Securities then outstanding will become due and
payable, without any declaration or other act on the part of the Trustee or any
Holder.

         The Holders of a majority in principal amount of the then outstanding
Securities, by written notice to the Company, the Subsidiary Guarantors and the
Trustee, may rescind and annul a declaration of acceleration and its
consequences if (i) the Company or any Subsidiary Guarantor has paid or
deposited with such Trustee a sum sufficient to pay (a) all overdue
installments of interest on all the Securities, (b) the principal of, and
premium, if any, on any Securities that has become due otherwise than by such
declaration of acceleration and interest thereon at the rate or rates
prescribed therefor in the Securities, (c) to the extent that payment of such
interest is lawful, interest on the defaulted interest at the rate or rates
prescribed therefor in the Securities, and (d) all money paid or advanced by
the Trustee thereunder and the reasonable compensation, expenses, disbursements
and advances of the Trustee, its agents and counsel; (ii) all Events of
Default, other than the non-payment of the principal of any Securities that
have become due solely by such declaration of acceleration, have been cured or
waived as provided in this Indenture; and (iii) the rescission would not
conflict with any judgment or decree of a court of competent jurisdiction. No
such rescission will affect any subsequent Event of Default or impair any right
consequent thereon.

SECTION 6.03.            OTHER REMEDIES.

         If an Event of Default occurs and is continuing, the Trustee may
pursue, in its own name and as trustee of an express trust, any available
remedy by proceeding at law or in equity to collect the payment of principal or
interest on the Securities or to enforce the performance of any provision of
the Securities or this Indenture.

         The Trustee may maintain a proceeding even if it does not possess any
of the Securities or does not produce any of them in the proceeding. A delay or
omission by the Trustee or any Holder in exercising any right or remedy
accruing upon an Event of Default shall not impair the right or remedy or
constitute a waiver of or acquiescence in the Event of Default. No remedy is
exclusive of any other remedy. All available remedies are cumulative.

SECTION 6.04.            WAIVER OF PAST DEFAULTS.

         Subject to Sections 6.07 and 9.02, the Holders of at least a majority
in principal amount of Securities then outstanding by notice to the Trustee may
waive an existing Default or Event of Default and its consequences, except a
Default or Event of Default in payment of principal, premium, if any, or
interest on the Securities, including any optional redemption payments or
Change of Control Offer or Asset Sale Offer payments.

SECTION 6.05.            CONTROL BY MAJORITY.

         The Holders of a majority in principal amount of the Securities will
have the right to direct the time, method and place of conducting any
proceeding for any remedy available to the Trustee or exercising any trust or
power conferred on such Trustee, provided that the Trustee may refuse to follow
any 


                                      -46-

<PAGE>   52
direction that (i) conflicts with law or this Indenture, (ii) is unduly
prejudicial to the rights of other Holders, or (iii) may involve the Trustee in
personal liability.

SECTION 6.06.            LIMITATION ON REMEDIES.

         Subject to Section 6.07, no Holder of any of the Securities will have
any right to institute any proceeding, judicial or otherwise, or for the
appointment of a receiver or trustee or pursue any remedy under this Indenture,
unless:

                  (i)  such Holder has previously given notice to the Trustee 
         of a continuing Event of Default,

                  (ii) the Holders of not less than 25% in principal amount of
         the outstanding Securities have made written request to such Trustee
         to institute proceedings in respect of such Event of Default in its
         own name as Trustee under this Indenture,

                  (iii)such Holder or Holders have offered and, if requested,
         provided to such Trustee indemnity satisfactory to the Trustee against
         the costs, expenses and liabilities to be incurred in compliance with
         such request,

                  (iv) such Trustee for 60 days after its receipt of such 
         notice, request and offer of indemnity has failed to institute any 
         such proceeding, and

                  (v)  no direction inconsistent with such written request has
         been given to such Trustee during such 60-day period by the Holders of
         a majority in principal amount of the outstanding Securities.

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

SECTION 6.07.            RIGHTS OF HOLDERS TO RECEIVE PAYMENT.

         Notwithstanding any other provision of this Indenture, the Holder of
any Securities will have the right, which is absolute and unconditional, to
receive payment of the principal of, premium, if any, and interest on such
Securities on the stated maturity therefor or redemption or purchase dates
thereof and to institute suit for the enforcement of any such payment, and such
right may not be impaired without the consent of such Holder.

SECTION 6.08.            COLLECTION SUIT BY TRUSTEE.

         If an Event of Default in payment of interest or principal specified
in Section 6.01(1) or (2) occurs and is continuing, the Trustee may recover
judgment in its own name and as trustee of an express trust against the Company
or any Subsidiary Guarantor for the whole amount of principal of and interest
on the Securities remaining unpaid and such further amounts as shall be
sufficient to cover the costs and expenses of collection, including the
reasonable compensation and expenses of the Trustee, its agents and counsel.



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<PAGE>   53
SECTION 6.09.            TRUSTEE MAY FILE PROOFS OF CLAIM.

         (a) The Trustee may file such proofs of claim and other papers or
documents as may be necessary or advisable in order to have the claims of the
Trustee and the Holders allowed in any judicial proceedings relative to the
Company, the Subsidiary Guarantors, their creditors or their property and may
collect and receive any money or other property payable or deliverable on any
such claims and to distribute the same.

         (b) Nothing herein contained shall be deemed to authorize the Trustee
to authorize or consent to or accept or adopt on behalf of any Holder any plan
of reorganization, arrangement, adjustment or composition affecting the
Securities or the rights of any Holder thereof, or to authorize the Trustee to
vote in respect of the claim of any Holder in any such proceeding.

SECTION 6.10.            PRIORITIES.

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

                  First:  to the Trustee for amounts due under Section 7.07;

                  Second: to Holders for amounts due and unpaid on the 
         Securities for principal and interest, ratably, without preference or 
         priority of any kind, according to the amounts due and payable on 
         the Securities for principal and interest, respectively; and

                  Third:  to the Company.

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

SECTION 6.11.            UNDERTAKING FOR COSTS.

         In any suit for the enforcement of any right or remedy under this
Indenture or in any suit against the Trustee for any action taken or omitted by
it as Trustee, a court in its discretion may require the filing by any party
litigant in the suit of an undertaking to pay the costs of the suit, and the
court in its discretion may assess reasonable costs, including reasonable
attorneys' fees, against any party litigant in the suit, having due regard to
the merits and good faith of the claims or defenses made by the party litigant.
This Section 6.11 does not apply to a suit by the Trustee, a suit by a Holder
pursuant to Section 6.07, or a suit by Holders of more than 10% in principal
amount of the then outstanding Securities.

                                 ARTICLE SEVEN

                                    TRUSTEE

SECTION 7.01.            DUTIES OF TRUSTEE.

         (a) If an Event of Default has occurred and is continuing, the Trustee
shall exercise such rights and powers vested in it by this Indenture and use
the same degree of care and skill in such exercise 



                                      -48-

<PAGE>   54
as a prudent person would exercise or use under the circumstances in the
conduct of such person's own affairs.

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

                  (1) The Trustee need perform only those duties that are
         specifically set forth (or incorporated by reference) in this
         Indenture and no others.

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

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

                  (1) This paragraph (c) does not limit the effect of paragraph 
         (b) of this Section.

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

                  (3) The Trustee shall not be liable with respect to action it
         takes or omits to take in good faith in accordance with a direction
         received by it pursuant to Section 6.05 or any other direction
         permitted by this Indenture, and the Trustee shall be entitled from
         time to time to request such a direction.

         (d) Every provision of this Indenture that in any way relates to 
the Trustee is subject paragraphs (a), (b) and (c) of this Section.

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

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

SECTION 7.02.            RIGHTS OF TRUSTEE.

         Subject to Section 7.01:

         (a) The Trustee may rely on and shall be protected in acting or
refraining from acting upon any document believed by it to be genuine and to
have been signed or presented by the proper person. The Trustee shall not be
bound to make any investigation into the facts or matters stated in any
resolution, certificate, statement, instrument, opinion, report, notice,
request, direction, consent, order, bond, debenture or other paper or document,
but the Trustee, in its discretion, may make such further 



                                      -49-

<PAGE>   55
inquiry or investigation into such facts or matters as it may see fit, and, if
the Trustee shall determine to make such further inquiry or investigation, it
shall be entitled to examine the books, records and premises of the Company,
personally or by agent or attorney, to the extent reasonably required by such
inquiry or investigation.

         (b) Before the Trustee acts or refrains from acting, it may require an
Officers' Certificate or an Opinion of Counsel or both. The Trustee shall not
be liable for any action it takes or omits to take in good faith in reliance on
such certificate or opinion.

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

         (d) The Trustee shall not be liable for any action it takes or omits
to take in good faith which it believes to be authorized or within its rights
or powers.

         (e) The Trustee may consult with counsel, and the advice or opinion of
counsel with respect to legal matters relating to this Indenture and the
Securities shall be full and complete authorization and protection from
liability in respect to any action taken, omitted or suffered by it hereunder
in good faith and in accordance with the advice or opinion of such counsel.

         (f) For all purposes under this Indenture, the Trustee shall not be
deemed to have notice or knowledge of any Event of Default (other than under
Section 6.01(1) or (2)) unless a Trust Officer knows of such Event of Default
or unless written notice of any Event of Default (other than under Section
6.01(1) or (2)) is received by the Trustee in accordance with and at its
address specified in Section 11.02 hereof and such notice references the
Securities generally, the Company or this Indenture.

SECTION 7.03.            INDIVIDUAL RIGHTS OF TRUSTEE.

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

SECTION 7.04.            TRUSTEE'S DISCLAIMER.

         The Trustee makes no representation as to the validity or adequacy of
this Indenture or the Securities, it shall not be accountable for the Company's
use of the proceeds from the Securities, and it shall not be responsible for
any statement of the Company in this Indenture or any statement in the
Securities other than its certificate of authentication.

SECTION 7.05.            NOTICE OF DEFAULTS.

         If a Default occurs and is continuing and if it is known to the
Trustee, the Trustee shall mail to each Holder pursuant to Section 11.02 a
notice of the Default within 90 days after it occurs. Except in the case of a
Default in any payment on any Security, the Trustee may withhold the notice if
and so long as the board of directors, executive committee or a trust committee
of its directors and/or officers in good faith determines that withholding the
notice is in the interests of Holders.




                                      -50-

<PAGE>   56
SECTION 7.06.            REPORTS BY TRUSTEE TO HOLDERS.

         Within 60 days after each May 15, beginning with May 15, 1998, and for
so long as Securities remain outstanding, the Trustee shall mail to each Holder
a brief report dated as of such May 15 that complies with TIA ss. 313(a), but
only if such report is required in any year under TIA ss. 313(a). The Trustee
also shall comply with TIA ss.ss. 313(b) and 313(c).

         A copy of each report at the time of its mailing to Holders shall be
mailed to the Company and filed with the SEC and each stock exchange on which
the Securities are listed in accordance with TIA ss. 313(d). The Company shall
notify the Trustee in writing if the Securities become listed on any national
securities exchange or of any delisting thereof.

SECTION 7.07.            COMPENSATION AND INDEMNITY.

         The Company shall pay the Trustee from time to time reasonable
compensation (including compensation for extraordinary services relating to
default administration) for its services (which compensation shall not be
limited by any provision of law in regard to the compensation of a trustee of
an express trust). The Company shall reimburse the Trustee upon request for all
reasonable out-of-pocket expenses, disbursements and advances incurred by it.
Such expenses may include the reasonable compensation and expenses of the
Trustee's agents and counsel.

         The Trustee shall not be under any obligation to institute any suit,
or take any remedial action under this Indenture, or to enter any appearance or
in any way defend any suit in which it may be a defendant, or to take any steps
in the execution of the trusts created hereby or thereby or in the enforcement
of any rights and powers under this Indenture, until it shall be indemnified to
its satisfaction against any and all reasonable expenses, disbursements and
advances incurred or made by the Trustee in accordance with any provision of
this Indenture, including compensation for services, costs, expenses, outlays,
counsel fees and other dis bursements, and against all liability not due to its
negligence or willful misconduct. The Company shall indemnify the Trustee
against any loss or liability incurred by it in connection with the acceptance
and administration of the trust and its duties hereunder as Trustee, Registrar
and/or Paying Agent, including the costs and expenses of defending itself
against any claim or liability in connection with the exercise or performance
of any of its powers or duties hereunder. The Trustee shall notify the Company
of any claim for which the Trustee may seek indemnity; however, unless the
position of the Company is prejudiced by such failure, the failure of the
Trustee to promptly notify the Company shall not limit the Trustee's right to
indemnification. The Company shall defend each such claim and the Trustee shall
cooperate in the defense. The Trustee may retain separate counsel and the
Company shall reimburse the Trustee for the reasonable fees and expenses of
such counsel. The Company need not pay for any settlement made without its
consent.

         The Company need not reimburse any expense or indemnify against any
loss or liability incurred by the Trustee through the Trustee's negligence or
willful misconduct.

         To satisfy the Company's payment obligations in this Section, the
Trustee shall have a claim prior to that of the Holders of the Securities on
all money or property held or collected by the Trustee, except that held in
trust to pay principal of and interest on particular Securities.

         When the Trustee incurs expenses or renders services after the
occurrence of any Event of Default specified in Sections 6.01(7) or (8), the
expenses and the compensation for the services are intended to constitute
expenses of administration under any Bankruptcy Law.



                                      -51-

<PAGE>   57
         The provisions of this Section 7.07 shall survive the termination of
this Indenture, as provided by Section 8.05.

SECTION 7.08.            REPLACEMENT OF TRUSTEE.

         A resignation or removal of the Trustee and appointment of a successor
Trustee shall become effective only upon the successor Trustee's acceptance of
appointment as provided in this Section 7.08.

         The Trustee may resign by so notifying the Company. The Holders of a
majority in principal amount of the Securities may remove the Trustee by so
notifying the Trustee and Company, in writing. The Company may remove the
Trustee if:

                  (1)   the Trustee fails to comply with Section 7.10;

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

                  (3)   a receiver or other public officer takes charge of the 
         Trustee or its property; or

                  (4)   the Trustee becomes incapable of acting as Trustee 
         hereunder.

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

         A successor Trustee shall deliver a written acceptance of its
appointment to the retiring Trustee and to the Company. Immediately after that,
the retiring Trustee shall transfer all property held by it as Trustee to the
successor Trustee, subject to the claim provided for in Section 7.07, the
resignation or removal of the retiring Trustee shall become effective, the
Company shall promptly pay all amounts due and payable to the retiring Trustee
pursuant to Section 7.07, and the successor Trustee shall have all the rights,
powers and duties of the Trustee under this Indenture. A successor Trustee
shall mail notice of its succession to each Holder. Notwithstanding replacement
of the Trustee pursuant to this Section 7.08, the Company's obligations under
Section 7.07 shall continue for the benefit of the retiring Trustee with
respect to expenses and liabilities incurred by it prior to such replacement.

         If a successor Trustee does not take office within 30 days after the
retiring Trustee resigns or is removed, the retiring Trustee, the Company or
the Holders of a majority in principal amount of the Securities may petition
any court of competent jurisdiction for the appointment of a successor Trustee.

         If the Trustee fails to comply with Section 7.10, any Holder who has
been a Holder of a Security for at least six months may petition any court of
competent jurisdiction for the removal of the Trustee and the appointment of a
successor Trustee. Any successor Trustee shall comply with TIA ss. 310(a)(5).

SECTION 7.09.            SUCCESSOR TRUSTEE BY MERGER, ETC.

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



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<PAGE>   58
the successor Trustee; provided such corporation or association shall be
otherwise eligible and qualified under this Article.

SECTION 7.10.            ELIGIBILITY; DISQUALIFICATION.

         This Indenture shall always have a Trustee who satisfies the
requirements of TIA ss. 310(a)(1), (2) and (5). The Trustee (together with its
parent bank holding company, if any) shall always have a combined capital and
surplus of at least $200,000,000 as set forth in its most recent published
annual report of condition. The Trustee shall also comply with TIA ss. 310(b).

SECTION 7.11.            PREFERENTIAL COLLECTION OF CLAIMS AGAINST COMPANY.

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

                                 ARTICLE EIGHT

                             DISCHARGE OF INDENTURE

SECTION 8.01.            TERMINATION OF COMPANY'S OBLIGATIONS.

         (a) This Indenture shall cease to be of further effect (subject to
Section 8.05) when all outstanding Securities theretofore authenticated and
issued hereunder have been delivered (other than any Securities which shall
have been destroyed, lost or stolen and which shall have been replaced or paid
as provided in Section 2.08) to the Trustee for cancellation and the Company
has paid all sums payable hereunder and under the Securities.

         (b) In addition to the provisions of Section 8.01(a), at the Company's
option, either (i) the Company and the Subsidiary Guarantors shall be deemed to
have been discharged from their obligations with respect to the Securities and
the provisions of this Indenture (subject to Section 8.05) on the 91st day
after the applicable conditions set forth below have been satisfied or (ii) the
Company and the Subsidiary Guarantors shall cease to be under any obligation to
comply with any term, provision or condition set forth in Sections 4.02, 4.03,
4.07 through 4.19, 5.01(2), 5.01(3), 5.01(4) and the last paragraph of Section
10.01 with respect to the Securities, and Sections 6.01(3) (to the extent that
such default results from the breach of any of the terms, provisions or
conditions of any of the foregoing Sections referred to in this clause (ii)),
6.01(4) (to the extent that such default results from the breach of any of the
terms, provisions or conditions of any of the foregoing Sections referred to in
this clause (ii)), 6.01(5) and (with respect to Material Subsidiaries) 6.01(7)
shall cease to be operative, at any time after the applicable conditions set
forth below have been satisfied:

                  (1) the Company or any Subsidiary Guarantor shall have
         deposited or caused to be deposited irrevocably with the Trustee as
         trust funds in trust, specifically pledged as security for, and
         dedicated solely to, the benefit of the Holders (A) money or (B) U.S.
         Government Obligations, which through the payment of interest and
         principal in respect thereof in accordance with their terms will
         provide (without any reinvestment of such interest or principal), not
         later than one day before the due date of any payment, money or (C) a
         combination of (A) and (B), in an amount sufficient, in the opinion
         (with respect to (B) and (C)) of a nationally recognized firm of
         independent public accountants expressed in a written certification
         thereof delivered to 



                                      -53-

<PAGE>   59

         the Trustee at or prior to the time of such deposit, to pay and 
         discharge each installment of principal of, and premium (if any) and 
         interest on, the outstanding Securities on the dates such installments 
         are due;

                  (2) no Default or Event of Default shall have occurred and be
         continuing on the date of such deposit or shall occur as a result of
         such deposit and such deposit will not result in a breach or violation
         of, or constitute a default under, any other instrument to which the 
         Company or a Subsidiary Guarantor or any Subsidiary is a party or by 
         which any of them is bound, as evidenced to the Trustee in an 
         Officers' Certificate delivered to the Trustee concurrently with such
         deposit;

                  (3) the Company shall have delivered to the Trustee an
         Opinion of Counsel to the effect that Holders will not recognize
         income, gain or loss for federal income tax purposes as a result of
         the Company's exercise of its option under this Section 8.01 and will
         be subject to federal income tax on the same amount and in the same
         manner and at the same time as would have been the case if such option
         had not been exercised, provided that in the case of the Securities
         being discharged pursuant to clause (i) of this Section 8.01(b), such
         opinion shall be based upon and shall identify a ruling by the
         Internal Revenue Service or a change in law to that effect (it being
         understood that (A) such Opinion of Counsel shall also state, if
         applicable, that such ruling or change in law is consistent with the
         conclusions reached in such Opinion of Counsel and (B) the Trustee
         shall be under no obligation to investigate the basis of correctness
         of such ruling);

                  (4) the Company shall have delivered to the Trustee an
         Opinion of Counsel to the effect that the Company's exercise of its
         option under this Section 8.01 will not result in any of the Company,
         the Trustee or the trust created by the Company's deposit of funds
         hereunder becoming or being deemed to be an "investment company" under
         the Investment Company Act of 1940, as amended;

                  (5) the Company or any Subsidiary Guarantor shall have paid 
         or duly provided for payment of all amounts then due to the Trustee 
         pursuant to Section 7.07; and

                  (6) the Company shall have delivered to the Trustee an
         Officers' Certificate and an Opinion of Counsel, each stating that all
         conditions precedent provided for in this Indenture relating to the
         satisfaction and discharge of this Indenture have been complied with.

         (c)      The Company or any Subsidiary Guarantor may make an 
irrevocable deposit to this Section 8.01.

SECTION 8.02.            APPLICATION OF TRUST MONEY.

         The Trustee shall hold in trust money or U.S. Government Obligations
deposited with it pursuant to Section 8.01. It shall apply the deposited money
and the money from U.S. Government Obligations through the Paying Agent and in
accordance with the provisions of the Securities and this Indenture to the
payment of principal of and interest on the Securities. Money and securities so
held in trust need not be segregated from other funds except to the extent
required by law.

         The term "U.S. Government Obligations" means direct obligations of the
United States for the payment of which the full faith and credit of the United
States is pledged.




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<PAGE>   60
SECTION 8.03.            REPAYMENT TO COMPANY.

         The Trustee and the Paying Agent shall promptly pay to the Company
upon request any money or securities held by them at any time in excess of
amounts required to pay principal of or interest on the Securities, which if
such request is made prior to the discharge of this Indenture, shall be money
or securities which in the opinion of a nationally recognized firm of
independent public accountants expressed in a certification thereof to the
Trustee are in excess of amounts required to pay principal of or interest on
the Securities. The Trustee and the Paying Agent shall pay to the Company upon
request any money held by them for the payment of principal or interest that
remains unclaimed for one year; provided, however, that the Trustee or such
Paying Agent before being required to make any such repayment, may at the
expense of the Company cause to be published once in a newspaper of general
circulation in the City of New York or mail to each such Holder notice that
such money remains unclaimed and that, after a date specified therein, which
shall not be less than 30 days from the date of such publication or mailing any
unclaimed balance of such money then remaining will be paid to the Company.
After repayment to the Company, any Holder entitled to such money shall
thereafter, as an unsecured general creditor, look (unless an applicable law
designates another Person) only to the Company for payment, and all liability
of the Trustee or such Paying Agent with respect to such trust money, and all
liability of the Company as trustee thereof, shall thereupon cease.

SECTION 8.04.            REINSTATEMENT.

         If the Trustee or Paying Agent is unable to apply any money or U.S.
Government Obligations in accordance with Section 8.01 by reason of any legal
proceeding or by reason of any order or judgment of any court or governmental
authority enjoining, restraining or otherwise prohibiting such application, the
Company's and the Subsidiary Guarantors' obligations under this Indenture and
the Securities shall be revived and reinstated as though no deposit had
occurred pursuant to Section 8.01 until such time as the Trustee or Paying
Agent is permitted to apply all such money or U.S. Government Obligations in
accordance with Section 8.01; provided, however, that if the Company or any
Subsidiary Guarantor has made any payment of interest on or principal of any
Securities because of the reinstatement of its obligations, the Company or such
Subsidiary Guarantor shall be subrogated to the rights of the Holders of such
Securities to receive such payment from the money or U.S. Government
Obligations held by the Trustee or Paying Agent.

SECTION 8.05.            SURVIVAL OF CERTAIN OBLIGATIONS.

         Notwithstanding the satisfaction and discharge of this Indenture and
of the Securities referred to in Section 8.01(b)(i) and Section 8.01(b)(ii),
the respective obligations of the Company, the Subsidiary Guarantors and the
Trustee under Sections 2.02, 2.03, 2.04, 2.05, 2.06, 2.07, 2.08, 2.12, 4.01
(with respect to Section 8.01(b)(i)), 4.04, 6.07, 7.07, 7.08, 8.02, 8.03, 8.04,
10.03, and 10.04 shall survive until the Securities are no longer outstanding,
and thereafter the obligations of the Company and the Trustee under Sections
7.07, 8.02, 8.03 and 8.04 shall survive. Nothing contained in this Article
Eight shall abrogate any of the obligations or duties of the Trustee under this
Indenture.



                                      -55-

<PAGE>   61
                                  ARTICLE NINE

                      AMENDMENTS, SUPPLEMENTS AND WAIVERS

SECTION 9.01.            WITHOUT CONSENT OF HOLDERS.

         The Company and the Trustee may amend or supplement this Indenture or
the Securities without notice to or consent of any Holder:

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

                  (2)  to comply with Sections 5.01, 10.02 or 10.06;

                  (3)  to provide for uncertificated Securities in addition to, 
         or in place of, certificated Securities;

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

                  (5)  to make any change that would provide any additional
         benefit or rights to the Holders or that does not adversely affect the
         rights of any Holder.

         Notwithstanding the above, the Trustee and the Company may not make
any change that adversely affects the legal rights of any Holders hereunder.

SECTION 9.02.            WITH CONSENT OF HOLDERS.

         Subject to Section 6.07, the Company, when authorized by a Board
Resolution, and the Trustee may amend or supplement this Indenture or the
Securities with the written consent of the Subsidiary Guarantors and the
Holders of at least a majority of the principal amount of the Securities then
outstanding, and the Holders of a majority in principal amount of the
Securities, together with the Subsidiary Guarantors, may waive compliance by
the Company or any Subsidiary with any provision of this Indenture or the
Securities. However, without the consent of each Holder affected, an amendment,
supplement or waiver, including a waiver pursuant to Section 6.04, may not:

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

                  (2)  reduce the rate of interest on the Securities;

                  (3)  reduce the principal amount of the Securities or extend 
         the maturity schedule of the Securities or modify the redemption or 
         repurchase provisions of the Securities;

                  (4)  waive a default in the payment of the principal, 
         premium (if any) or interest on the Securities;


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

                  (6)  subordinate the Securities in a manner that is adverse 
         to the Holders; or




                                      -56-

<PAGE>   62
                  (7)  make any change in Section 6.04 or Section 6.07 hereof 
         or in this sentence of this Section 9.02.

         It shall not be necessary for the consent of the Holders under this
Section 9.02 to approve the particular form of any proposed amendment,
supplement or waiver, but it shall be sufficient if such consent approves the
substance thereof. Any amendment, waiver or consent shall be deemed effective
upon receipt by the Trustee of the necessary consents and shall not require
execution of any supplemental indenture to be effective.

         After an amendment, supplement or waiver under this Section 9.02
becomes effective, the Company shall mail to the Holders of each Security
affected thereby, with a copy to the Trustee, a notice briefly describing the
amendment, supplement or waiver. Any failure of the Company to mail such
notice, or any defect therein, shall not, however, in any way impair or affect
the validity of any such amendment, waiver, consent or supplemental indenture.
Except as otherwise provided in Section 6.04 and this Section 9.02, the Holders
of a majority in aggregate principal amount of the Securities then outstanding
may waive compliance in a particular instance by the Company or the Subsidiary
Guarantors with any provisions of this Indenture or the Securities.

SECTION 9.03.            COMPLIANCE WITH TRUST INDENTURE ACT.

         Every amendment to or supplement of this Indenture or the Securities
shall comply with the TIA as then in effect.

SECTION 9.04.            REVOCATION AND EFFECT OF CONSENTS.

         A consent to an amendment, supplement or waiver by a Holder of a
Security shall bind the Holder and every subsequent Holder of a Security or
portion of a Security that evidences the same debt as the consenting Holder's
Security, even if notation of the consent is not made on any Security. However,
until an amendment, supplement or waiver becomes effective, any such Holder or
subsequent Holder may revoke the consent as to his Security or portion of a
Security. For such revocation to be effective, the Trustee must receive the
notice of revocation before the date the amendment, supplement or waiver
becomes effective.

         After an amendment, supplement or waiver becomes effective, it shall
bind every Holder unless it makes a change described in any of clauses (1)
through (7) of Section 9.02. In that case the amendment, supplement or waiver
shall bind each Holder of a Security who has consented to it and every
subsequent Holder of a Security or portion of a Security that evidences the
same debt as the consenting Holder's Security.

SECTION 9.05.            NOTATION ON OR EXCHANGE OF SECURITIES.

         If an amendment, supplement or waiver changes the terms of a Security,
the Trustee may require the Holder of the Security to deliver it to the
Trustee. The Trustee may place an appropriate notation on the Security about
the changed terms and return it to the Holder. Alternatively, if the Company or
the Trustee so determines, the Company in exchange for the Security shall issue
and the Trustee shall authenticate a new Security that reflects the changed
terms.




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<PAGE>   63
SECTION 9.06.            TRUSTEE PROTECTED.

         Upon the request of the Company accompanied by a resolution of its
Board of Directors authorizing the execution of any such amended or
supplemental Indenture or waiver, and upon the filing with the Trustee of
evidence satisfactory to the Trustee of the consent of the Holders of
Securities, if required by Section 9.02, the Trustee shall sign any amendment
or supplement or waiver authorized pursuant to this Article if the amendment or
supplement or waiver does not adversely affect the rights, duties, liabilities
or immunities of the Trustee. If it does adversely affect the rights, duties,
liabilities or immunities of the Trustee, the Trustee may but need not sign it.
In signing such amendment or supplement or waiver the Trustee shall be entitled
to receive, and (subject to Article Seven) shall be fully protected in relying
upon, an Opinion of Counsel stating that such amendment or supplement or waiver
is authorized or permitted by and complies with this Indenture, is the legal,
valid and binding obligation of the Company or the applicable Subsidiary, or
any combination of the foregoing Persons as applicable, enforceable against it
or them, as applicable, in accordance with its terms (subject to customary
qualifications and exceptions), and that all necessary governmental consents
have been obtained. The Company may not sign an amendment or supplement until
the Board of Directors of the Company approves it.

                                  ARTICLE TEN

                             SUBSIDIARY GUARANTEES

SECTION 10.01.           UNCONDITIONAL GUARANTEE.

         Each Subsidiary Guarantor hereby unconditionally, jointly and
severally, guarantees (such guarantee to be referred to herein as the
"Subsidiary Guarantee") to each Holder of Securities authenticated and
delivered by the Trustee and to the Trustee and its successors and assigns,
that:

                  (1) the principal of, premium, if any, and interest on the
         Securities will be promptly paid in full when due, whether at
         maturity, by acceleration, redemption or otherwise, and interest on
         the overdue principal of and interest on the Securities, if any, to
         the extent lawful, and all other obligations of the Company to the
         Holders or the Trustee hereunder or thereunder will be promptly paid
         in full or performed, all in accordance with the terms hereof and
         thereof; and

                  (2) in case of any extension of time of payment or renewal of
         any Securities or of any such other obligations, that same will be
         promptly paid in full when due or performed in accordance with the 
         terms of the extension or renewal, whether at stated maturity, by 
         acceleration or otherwise,

subject, however, in the case of clauses (1) and (2) above, to the limitations
set forth in Section 10.04.

         Failing payment when due of any amount so guaranteed or any
performance so guaranteed for whatever reason, the Subsidiary Guarantors will
be jointly and severally obligated to pay the same immediately. Each Subsidiary
Guarantor hereby agrees that its obligations hereunder shall be unconditional,
irrespective of the validity, regularity or enforceability of the Securities or
this Indenture, the absence of any action to enforce the same, any waiver or
consent by any Holder of the Securities with respect to any provisions hereof
or thereof, the recovery of any judgment against the Company, any action to
enforce the same or any other circumstance which might otherwise constitute a
legal or equitable discharge or defense of a guarantor. Each Subsidiary
Guarantor hereby, to the extent permitted by law, 




                                      -58-

<PAGE>   64
waives diligence, presentment, demand of payment, filing of claims with a court
in the event of insolvency or bankruptcy of the Company, any right to require a
proceeding first against the Company, protest, notice, notice of intent to
accelerate, notice of acceleration, and all other notices and all demands
whatsoever and covenants that this Subsidiary Guarantee will not be discharged
except by complete performance of the obligations contained in the Securities,
this Indenture and in this Subsidiary Guarantee. If any Holder or the Trustee
is required by any court or otherwise to return to the Company, any Subsidiary
Guarantor, or any custodian, trustee, liquidator or other similar official
acting in relation to the Company or any Subsidiary Guarantor, any amount paid
by the Company or any Subsidiary Guarantor to the Trustee or such Holder, this
Subsidiary Guarantee, to the extent theretofore discharged, shall be reinstated
in full force and effect. Each Subsidiary Guarantor agrees it shall not be
entitled to any right of subrogation in relation to the Holders in respect of
any obligations guaranteed hereby until payment in full of all obligations
guaranteed hereby. Each Subsidiary Guarantor further agrees that, as between
each Subsidiary Guarantor, on the one hand, and the Holders and the Trustee, on
the other hand, (x) the maturity of the obligations guaranteed hereby may be
accelerated as provided in Article Six for the purposes of this Subsidiary
Guarantee, notwithstanding any stay, injunction or other prohibition preventing
such acceleration in respect of the obligations guaranteed hereby, and (y) in
the event of any acceleration of such obligations as provided in Article Six,
such obligations (whether or not due and payable) shall forthwith become due
and payable by each Subsidiary Guarantor for the purpose of this Subsidiary
Guarantee.

         The Company agrees to cause (a) each Person (other than an
Unrestricted Subsidiary and any Exempt Foreign Subsidiary) that shall become a
Material Subsidiary after the date of the Issue Date, and (b) each Subsidiary
that is not a Subsidiary Guarantor on the Issue Date that after the Issue Date
incurs any Indebtedness with respect to any Indebtedness of the Company or any
other Subsidiary, to execute and deliver a supplement to this Indenture
agreeing to be bound by its terms applicable to a Subsidiary Guarantor and
pursuant to which such Person will guarantee the payment of the Securities on
the same terms and conditions as the Subsidiary Guarantees by the Subsidiary
Guarantors.

SECTION 10.02.           SUBSIDIARY GUARANTORS MAY CONSOLIDATE, ETC., ON 
                         CERTAIN TERMS.

         (a) Except as set forth in Article Five, nothing contained in this
Indenture or in any of the Securities shall prevent any consolidation or merger
of a Subsidiary Guarantor with or into the Company or another Subsidiary
Guarantor or shall prevent any sale or conveyance of the property of a
Subsidiary Guarantor as an entirety or substantially as an entirety, to the
Company or another Subsidiary Guarantor.

         (b) Except as set forth in Article Five hereof, nothing contained in
this Indenture or in any of the Securities shall prevent any consolidation or
merger of a Subsidiary Guarantor with or into a Person other than the Company
or a Subsidiary Guarantor that is a Wholly Owned Subsidiary (whether or not
affiliated with the Subsidiary Guarantor that is a Wholly Owned Subsidiary), or
successive consolidations or mergers in which a Subsidiary Guarantor or its
successor or successors shall be a party or parties, or shall prevent any sale
or conveyance of the property of a Subsidiary Guarantor as an entirety or
substantially as an entirety, to a Person other than the Company or another
Subsidiary Guarantor that is a Wholly Owned Subsidiary (whether or not
affiliated with the Subsidiary Guarantor that is a Wholly Owned Subsidiary)
authorized to acquire and operate the same; provided, however, that, (i)
immediately after such transaction, and giving effect thereto, no Default or
Event of Default shall have occurred as a result of such transaction and be
continuing, (ii) such transaction shall not violate any of the covenants in
Sections 4.02, 4.09 through 4.16, 4.18 and 4.19, and (iii) except to the extent
that Section 10.03 would result in the release of such Subsidiary Guarantor,
each Subsidiary Guarantor hereby covenants and agrees that, upon any such
consolidation, merger, sale or conveyance, such Subsidiary 





                                      -59-

<PAGE>   65
Guarantor's Subsidiary Guarantee set forth in this Article Ten, and the due and
punctual performance and observance of all of the covenants and conditions of
this Indenture to be performed by such Subsidiary Guarantor, shall be expressly
assumed (in the event that the Subsidiary Guarantor is not the surviving Person
in the merger), by supplemental indenture satisfactory in form to the Trustee,
executed and delivered to the Trustee, by the Person formed by such
consolidation, or into which the Subsidiary Guarantor shall have merged, or by
the Person that shall have acquired such property. In the case of any such
consolidation, merger, sale or conveyance and upon the assumption by the
successor Person, by supplemental indenture executed and delivered to the
Trustee and satisfactory in form to the Trustee of the due and punctual
performance of all of the covenants and conditions of this Indenture to be
performed by the Subsidiary Guarantor, such successor Person shall succeed to
and be substituted for the Subsidiary Guarantor with the same effect as if it
had been named herein as a Subsidiary Guarantor.

SECTION 10.03.           RELEASE OF A SUBSIDIARY GUARANTOR.

         Upon the sale or other disposition of a Subsidiary Guarantor (or all
or substantially all of its properties and assets), which is otherwise in
compliance with the terms of this Indenture, including but not limited to the
provisions of Section 10.02, such Subsidiary Guarantor shall be deemed released
from all of the Subsidiary Guarantee and related obligations in this Indenture;
provided, however, that any such termination shall occur only to the extent
that all obligations of such Subsidiary Guarantor under all of its guarantees
of, and under all of its pledges of assets or other security interests which
secure, other Indebtedness of the Company or any Subsidiary shall also
terminate or be released upon such sale or transfer. Each Subsidiary Guarantor
that is designated as an Unrestricted Subsidiary in accordance with this
Indenture shall be released from all of its Subsidiary Guarantee and related
obligations set forth in this Indenture for so long as it remains an
Unrestricted Subsidiary. The Trustee shall deliver an appropriate instrument
evidencing such release upon receipt of a request by the Company accompanied by
an Officers' Certificate and an Opinion of Counsel certifying that such sale or
other disposition was made by the Company in accordance with the provisions of
this Indenture. Any Subsidiary Guarantor not so released remains liable for the
full amount of principal of and interest on the Securities as provided in this
Article Ten.

SECTION 10.04.           LIMITATION OF SUBSIDIARY GUARANTOR'S LIABILITY.

         Each Subsidiary Guarantor and by its acceptance hereof each
beneficiary hereof, hereby confirms that it is the intention of all such
parties that Subsidiary Guarantee by such Subsidiary Guarantor not constitute a
fraudulent transfer or conveyance for purposes of any federal or state law. To
effectuate the foregoing intention, each such beneficiary and each Subsidiary
Guarantor hereby irrevocably agree that the obligations of each Subsidiary
Guarantor under its Subsidiary Guarantee shall be limited to the maximum amount
as will, after giving effect to all other contingent and fixed liabilities
(including, but not limited to, Guarantor Senior Indebtedness of each
Subsidiary Guarantor) of such Subsidiary Guarantor and after giving effect to
any collections from or payments made by or on behalf of any other Subsidiary
Guarantor in respect of the obligations of such other Subsidiary Guarantor
under its Subsidiary Guarantee or pursuant to Section 10.05, result in the
obligations of such Subsidiary Guarantor under its Subsidiary Guarantee not
constituting a fraudulent conveyance or fraudulent transfer under federal or
state law. This Section 10.04 is for the benefit of the creditors of each
Subsidiary Guarantor, and, for purposes of applicable fraudulent transfer and
fraudulent conveyance law, any Indebtedness of a Subsidiary Guarantor pursuant
to the Credit Facility shall be deemed to have been incurred prior to the
incurrence by such Subsidiary Guarantor of its liability under the Subsidiary
Guarantee.



                                      -60-

<PAGE>   66
SECTION 10.05.           CONTRIBUTION.

         In order to provide for just and equitable contribution among the
Subsidiary Guarantors, the Subsidiary Guarantors agree, inter se, that in the
event any payment or distribution is made by any Subsidiary Guarantor (a
"Funding Guarantor") under the Subsidiary Guarantee, such Funding Guarantor
shall be entitled to a contribution from each other Subsidiary Guarantor in a
pro rata amount based on the Adjusted Net Assets of each Subsidiary Guarantor
(including the Funding Guarantor) for all payments, damages and expenses
incurred by that Funding Guarantor in discharging the Company's obligations
with respect to the Securities or any other Subsidiary Guarantor's obligations
with respect to the Subsidiary Guarantee.

SECTION 10.06.           EXECUTION AND DELIVERY OF SUBSIDIARY GUARANTEE.

         To evidence its guarantee set forth in Section 10.01, each Subsidiary
Guarantor hereby agrees to execute its Subsidiary Guarantee in substantially
the form of Exhibit A-1 to be endorsed on each Security ordered to be
authenticated and delivered by the Trustee and each Subsidiary Guarantor agrees
that this Indenture shall be executed on behalf of each Subsidiary Guarantor by
its President or one of its Vice Presidents and attested to by an Officer or a
Secretary or Assistant Secretary. Each Subsidiary Guarantor hereby agrees that
its Subsidiary Guarantee set forth in Section 10.01 shall remain in full force
and effect notwithstanding any failure to endorse on each Security a notation
of such Subsidiary Guarantee. Each such Subsidiary Guarantee shall be signed on
behalf of each Subsidiary Guarantor by one Officer, (who shall have been duly
authorized by all requisite corporate actions) prior to the authentication of
the Security on which it is endorsed, and the delivery of such Security by the
Trustee, after the authentication thereof hereunder, shall constitute due
delivery of the Subsidiary Guarantee set forth in this Indenture on behalf of
the Subsidiary Guarantors. Such signatures upon the Subsidiary Guarantee may be
by manual or facsimile signature of such officers and may be imprinted or
otherwise reproduced on the Subsidiary Guarantee, and in case any such officer
who shall have signed the Subsidiary Guarantee shall cease to be such officer
before the Security on which such Subsidiary Guarantee is endorsed shall have
been authenticated and delivered by the Trustee or disposed of by the Company,
such Security nevertheless may be authenticated and delivered or disposed of as
though the person who signed the Subsidiary Guarantee had not ceased to be such
officer of the Subsidiary Guarantor.

SECTION 10.07.           SEVERABILITY.

         In case any provision of any Subsidiary Guarantee shall be invalid,
illegal or unenforceable, that portion of such provision that is not invalid,
illegal or unenforceable shall remain in effect, and the validity, legality,
and enforceability of the remaining provisions shall not in any way be affected
or impaired thereby.



                                      -61-

<PAGE>   67
                                 ARTICLE ELEVEN

                                 MISCELLANEOUS

SECTION 11.01.           TRUST INDENTURE ACT CONTROLS.

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

SECTION 11.02.           NOTICES.

         Any notice or communication shall be sufficiently given if in writing
and delivered in person or mailed by certified or registered mail (return
receipt requested) or sent by overnight air courier guaranteeing next-day
delivery, addressed as follows or by facsimile transmission:

                  If to the Company or any Subsidiary Guarantor:

                           Dailey Petroleum Services Corp.
                           One Lawrence Center
                           2507 North Frazier
                           Conroe, Texas  77305
                           Telecopy No.:  (409) 760-3304
                           Attention:  Chief Financial Officer

                  Until written notice is given to the Trustee to the contrary,
                  the office or agency maintained in the City of New York by
                  the Company where Securities may be surrendered for 
                  registration of transfer or exchange or for presentation for 
                  payment and where notices and demands to or upon the Company 
                  in respect of the Securities and this Indenture may be 
                  served, shall be the offices of the Trustee located in the 
                  City of New York which are so designated immediately 
                  hereinafter.

                  If to the Trustee:

                           For registration, transfer, exchange, payment and
                           notices and demands to or upon Company in respect of
                           the Securities (with copy of each such notice or
                           demand sent to Trustee's office in Dallas, Texas as
                           set forth below):

                                    By hand:
                                    U.S. Trust Company of Texas, N.A.
                                    111 Broadway, L.L.
                                    New York, New York  10006
                                    Telephone:  (212) 374-4056
                                    Attention:  Corporate Trust


                                      -62-

<PAGE>   68
                                    By mail:
                                    U.S. Trust Company of Texas, N.A.
                                    P. O. Box 841
                                    Cooper Station
                                    New York, New York 10276

                           For all other communications relating to the
Securities:

                                    U.S. Trust Company of Texas, N.A.
                                    2001 Ross Avenue, Suite 2700
                                    Dallas, Texas  75201
                                    Telephone: (214) 754-1254
                                    Facsimile No.:  (214) 754-1303
                                    Attention:  Corporate Trust

         The Company or any Subsidiary Guarantor or the Trustee, by notice to
the other, may designate additional or different addresses for subsequent
notices or communications.

         All notices and communications (other than those sent to Holders)
shall be deemed to have been duly given: at the time delivered by hand, if
personally delivered; 5 Business Days after being deposited in the United
States mail, postage prepaid, if mailed; when receipt acknowledged, if sent by
facsimile; the next Business Day after timely delivery to the courier, if sent
for overnight delivery by a courier guaranteeing next-day delivery; and the
second Business Day after timely delivery to the courier, if sent for
second-day delivery by a courier guaranteeing second-day delivery.

         Any notice or communication mailed to a Holder shall be mailed to him
by first-class mail at his address as it appears on the registration books of
the Registrar and shall be sufficiently given to him if so mailed within the
time prescribed.

         Failure to mail a notice or communication to a Holder or any defect in
it shall not affect its sufficiency with respect to other Holders. If a notice
or communication is mailed in the manner provided above, it is duly given,
whether or not the addressee receives it. If the Company mails notice or
communications to Holders it shall mail a copy to the Trustee and each Agent at
the same time. All notices or communications shall be in writing.

SECTION 11.03.           COMMUNICATION BY HOLDERS WITH OTHER HOLDERS.

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

SECTION 11.04.           CERTIFICATE AND OPINION AS TO CONDITIONS PRECEDENT.

         Upon any request or application by the Company and/or any Subsidiary
Guarantor to the Trustee to take any action under this Indenture, the Company
and/or such Subsidiary Guarantor, as the case may be, shall furnish to the
Trustee:



                                      -63-

<PAGE>   69
                  (1) an Officers' Certificate stating that, in the opinion of
         the signers, the conditions precedent, if any, provided for in this
         Indenture relating to the proposed action have been complied with; and

                  (2) an Opinion of Counsel stating that, in the opinion of
         such counsel, such conditions precedent have been complied with.

SECTION 11.05.        STATEMENTS REQUIRED IN CERTIFICATE OR OPINION.

         Each certificate or opinion with respect to compliance with a
condition or covenant provided for in this Indenture shall include:

                  (1) a statement that each person making such certificate or 
         opinion has read such covenant or condition;

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

                  (3) a statement that, in the opinion of each such person, he
         or she has made such examination or investigation as is necessary to
         enable him or her to express an informed opinion as to whether or not
         such covenant or condition has been complied with; and

                  (4) a statement as to whether or not, in the opinion of each
         such person, such covenant or condition has been complied with.

SECTION 11.06.        RULES BY TRUSTEE AND AGENTS.

         The Trustee may make reasonable rules for action by or a meeting of
Holders. The Registrar or Paying Agent may make reasonable rules for its
functions.

SECTION 11.07.        LEGAL HOLIDAYS.

         A "Legal Holiday" is a Saturday, a Sunday, or a day on which banks and
trust companies in The City of New York are not required by law or executive
order to be open. If a payment date is a Legal Holiday at a place of payment,
payment may be made at the place on the next succeeding day that is not a Legal
Holiday, without additional interest.

SECTION 11.08.        GOVERNING LAW.

         THIS INDENTURE AND THE SECURITIES AND THE SUBSIDIARY GUARANTEES SHALL
BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW
YORK WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAWS TO THE
EXTENT THAT THE APPLICATION OF THE LAW OF ANOTHER JURISDICTION WOULD BE
REQUIRED THEREBY.



                                      -64-

<PAGE>   70
SECTION 11.09.           NO ADVERSE INTERPRETATION OF OTHER AGREEMENTS.

         This Indenture may not be used to interpret another indenture, loan or
debt agreement of the Company or a Subsidiary. Any such indenture, loan or debt
agreement may not be used to interpret this Indenture.

SECTION 11.10.           NO RECOURSE AGAINST OTHERS.

         ALL LIABILITY DESCRIBED IN PARAGRAPH 18 OF THE SECURITIES OF ANY
DIRECTOR, OFFICER, EMPLOYEE OR STOCKHOLDER, AS SUCH, OF THE COMPANY, THE
SUBSIDIARY GUARANTORS OR THE TRUSTEE IS WAIVED AND RELEASED.

SECTION 11.11.           SUCCESSORS.

         All agreements of the Company and Subsidiaries in this Indenture and
the Securities shall bind their successor. All agreements of the Trustee in
this Indenture shall bind its successor.

SECTION 11.12.           DUPLICATE ORIGINALS.

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

SECTION 11.13.           SEVERABILITY.

         In case any provision in this Indenture or in the Securities shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby,
and a Holder shall have no claim therefor against any party hereto.

SECTION 11.14.           COUNTERPARTS.

         This Indenture may be executed in one or more counterparts, and by
each of the parties hereto on separate counterparts, each of which shall be
deemed to be an original, but all such counterparts shall together constitute
one and the same instrument.



                                      -65-
<PAGE>   71
                                   SIGNATURES

         IN WITNESS WHEREOF, the parties hereto have caused this Indenture to
be duly executed, and their respective corporate seals to be hereunto affixed
and attested, all as of the date first written above.

Dated:  August 19, 1997

                                   DAILEY PETROLEUM SERVICES CORP.


                                   By   /s/ JAMES F. FARR
                                        --------------------------------------
                                        JAMES F. FARR
                                        President and Chief Executive Officer


                                   U.S. TRUST COMPANY OF TEXAS, N.A., Trustee


                                   By
                                        /s/ BILL BARBER
                                        --------------------------------------
                                        Name:  BILL BARBER
                                        Title:  VICE PRESIDENT


                                   SUBSIDIARY GUARANTORS:

                                   DAILEY INTERNATIONAL, INC., a Delaware
                                     corporation


                                   By   /s/ JAMES F. FARR
                                        --------------------------------------
                                        JAMES F. FARR
                                        President


                                   DAILEY INTERNATIONAL SALES CORPORATION, a 
                                   Delaware corporation



                                   By   /s/ JAMES F. FARR
                                        --------------------------------------
                                        JAMES F. FARR
                                        President



                                      -66-

<PAGE>   72

                                    COLUMBIA PETROLEUM SERVICES CORP.,
                                      a Delaware corporation


                                   By   /s/ JAMES F. FARR
                                        --------------------------------------
                                        JAMES F. FARR
                                        President


                                    INTERNATIONAL PETROLEUM SERVICES, INC.,
                                      a Delaware corporation



                                   By   /s/ JAMES F. FARR
                                        --------------------------------------
                                        JAMES F. FARR
                                        President


                                   DAILEY ENVIRONMENTAL REMEDIATION 
                                    TECHNOLOGIES, INC., a Texas corporation



                                   By   /s/ JAMES F. FARR
                                        --------------------------------------
                                        JAMES F. FARR
                                        President


                                   DAILEY WORLDWIDE SERVICES, CORP., a Texas 
                                     corporation



                                   By   /s/ JAMES F. FARR
                                        --------------------------------------
                                        JAMES F. FARR
                                        President


                                   AIR DRILLING INTERNATIONAL, INC., a Delaware
                                    corporation



                                   By   /s/ DAVID T. TIGHE
                                        --------------------------------------
                                        DAVID T. TIGHE
                                        Vice President




                                      -67-

<PAGE>   73

                                   AIR DRILLING SERVICES, INC., a Wyoming
                                       corporation

                                   By   /s/ DAVID T. TIGHE
                                        --------------------------------------
                                        DAVID T. TIGHE
                                        Vice President




                                      -68-

<PAGE>   74
                                                                      EXHIBIT A


                               [Form of Security]


[If a Series A Security or a Series B Security constituting a Transfer 
Restricted Security --

         THE NOTES EVIDENCED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE
SECURITIES LAWS, AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD WITHIN THE UNITED
STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT OF, U.S. PERSONS EXCEPT AS SET
FORTH IN THE FOLLOWING SENTENCE. BY ITS ACQUISITION HEREOF, THE HOLDER (1)
REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN RULE
144A UNDER THE SECURITIES ACT) OR (B) IT IS AN INSTITUTIONAL "ACCREDITED
INVESTOR" (AS DEFINED IN RULE 501(a)(1), (2), (3) OR (7) UNDER THE SECURITIES
ACT) ("INSTITUTIONAL ACCREDITED INVESTOR") OR (C) IT IS NOT A U.S. PERSON AND
IS ACQUIRING THE NOTES EVIDENCED HEREBY IN AN OFFSHORE TRANSACTION, (2) AGREES
THAT IT WILL NOT WITHIN TWO YEARS AFTER THE ORIGINAL ISSUANCE OF THE NOTES
EVIDENCED HEREBY RESELL OR OTHERWISE TRANSFER THE NOTES EVIDENCED HEREBY,
EXCEPT (A) TO DAILEY PETROLEUM SERVICES CORP. (THE "COMPANY"), (B) INSIDE THE
UNITED STATES TO A QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A
UNDER THE SECURITIES ACT, (C) INSIDE THE UNITED STATES TO AN INSTITUTIONAL
ACCREDITED INVESTOR THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO U.S. TRUST
COMPANY OF TEXAS, N.A., AS TRUSTEE, A SIGNED LETTER CONTAINING CERTAIN
REPRESENTATIONS AND AGREEMENTS RELATING TO THE RESTRICTIONS ON TRANSFER OF THE
NOTES EVIDENCED HEREBY (THE FORM OF WHICH LETTER CAN BE OBTAINED FROM SUCH
TRUSTEE), (D) OUTSIDE THE UNITED STATES TO FOREIGN PURCHASERS IN OFFSHORE
TRANSACTIONS MEETING THE REQUIREMENTS OF RULE 904 OF REGULATION S UNDER THE
SECURITIES ACT, (E) PURSUANT TO THE EXEMPTION FROM REGISTRATION PROVIDED BY
RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE), OR (F) PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT AND (3) AGREES THAT
IT WILL DELIVER TO EACH PERSON TO WHOM THE NOTES EVIDENCED HEREBY ARE
TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. IN CONNECTION
WITH ANY TRANSFER OF THE NOTES EVIDENCED HEREBY WITHIN TWO YEARS AFTER THE
ORIGINAL ISSUANCE OF SUCH NOTES, THE HOLDER MUST PRIOR TO SUCH TRANSFER,
FURNISH TO U.S. TRUST COMPANY OF TEXAS, N.A., AS TRUSTEE, A SIGNED LETTER
CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS RELATING TO THE RESTRICTIONS
ON TRANSFER OF THE NOTES EVIDENCED HEREBY (THE FORM OF WHICH LETTER CAN BE
OBTAINED FROM SUCH TRUSTEE). IF THE PROPOSED TRANSFEREE IS AN INSTITUTIONAL
ACCREDITED INVESTOR, THE HOLDER MUST, PRIOR TO SUCH TRANSFER, FURNISH TO THE
COMPANY AND U.S. TRUST COMPANY OF TEXAS, N.A., AS TRANSFER AGENT, SUCH
CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS THEY MAY REASONABLY
REQUIRE TO CONFIRM THAT SUCH TRANSFER IS BEING MADE PURSUANT TO AN EXEMPTION
FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE
SECURITIES ACT. THIS LEGEND WILL BE REMOVED AFTER THE EXPIRATION OF TWO YEARS
FROM THE ORIGINAL ISSUANCE OF THE NOTES EVIDENCED HEREBY IF THE PROVISIONS OF
SECTION 2.14(a)(i) OF THE INDENTURE ARE SATISFIED. AS USED HEREIN, THE TERMS
"OFFSHORE TRANSACTION", "UNITED STATES" AND "U.S. PERSON" HAVE THE RESPECTIVE
MEANINGS GIVEN TO THEM IN REGULATION S UNDER THE SECURITIES ACT.



                                      A-1

<PAGE>   75
REGISTERED

                          9 3/4% SENIOR NOTE DUE 2007

                                                       CUSIP:__________________
No. R-_________________                                           $ 115,000,000

                        DAILEY PETROLEUM SERVICES CORP.
                            (a Delaware corporation)

promises to pay to    
or registered assigns ---------------------------
the principal sum of                             Dollars on August 15, 2007
                      ---------------------------

                  Interest Payment Dates:       February 15 and August 15

                  Record Dates:                 February 1 and August 1

Dated:                                          DAILEY PETROLEUM SERVICES CORP.

Attest:                                         By:


-------------------------------                 -------------------------------
         Secretary                                         President

                                     [Seal]
Authenticated:


U.S. TRUST COMPANY OF TEXAS, N.A.,
as Trustee


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

OR

as Authenticating Agent


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

[Seal]

                                      A-2

<PAGE>   76
                           [Reverse Side of Security]


                        DAILEY PETROLEUM SERVICES CORP.

                          9 3/4% Senior Note Due 2007


1.       Interest.

         Dailey Petroleum Services Corp., a Delaware corporation (the
"Company"), promises to pay interest on the principal amount of this Security
at the rate per annum shown above. The Company will pay interest semiannually
on February 15 and August 15 of each year, commencing [if a Series A Security -
on February 15, 1998 and continuing semiannually thereafter, on August 15 and
February 15 in each year] [if a Series B Security - on the first February 15 or
August 15 following the original issuance of the Series B Securities and
continuing semiannually thereafter, on February 15 and August 15 in each year,
from the date of the original issuance of the Series B Securities], or from the
most recent date to which interest has been paid or duly provided for, until
the principal hereof is paid or duly provided for. Interest will be computed on
the basis of a 360-day year of twelve 30-day months. Accrued but unpaid
interest on any Series A Security that is exchanged for a Series B Security
pursuant to the Registration Rights Agreement shall be paid on or before the
first interest payment date on the Series B Securities.

         The interest rate on the Securities is subject to increase under
certain circumstances described in Section 4 of the Registration Rights
Agreement.

         The Company shall pay interest on overdue principal of and interest on
overdue installments of interest, to the extent lawful, at a rate equal to the
rate of interest otherwise payable on the Securities.

2.       Method of Payment.

         The Company will pay interest on the Securities to the persons who are
registered holders of Securities at the close of business on the February 1 or
August 1 immediately preceding the interest payment date even though Securities
are cancelled after the record date and on or before the interest payment date.
Holders must surrender Securities to a Paying Agent to collect principal
payments. The Company will pay principal of and interest on the Securities in
money of the United States that at the time of payment is legal tender for
payment of public and private debts. The Company may pay principal or interest
by check payable in such money or by wire transfer of immediately available
funds. If paying by check, the Company may mail such check to a Holder's
registered address.

3.       Paying Agent and Registrar.

         Initially, the Trustee will act as Paying Agent and Registrar. The
Company may change any Paying Agent, Registrar or co-registrar without notice.
The Company or any of its Subsidiaries may act as Paying Agent or Registrar.



                                      A-3
<PAGE>   77
4.       Indenture and Subsidiary Guarantees.

         The Company issued the Securities under an Indenture dated as of
August 19, 1997 (the "Indenture") among the Company, the Subsidiary Guarantors,
and the Trustee. Capitalized terms herein are used as defined in the Indenture
unless otherwise defined herein. The terms of the Securities include those
stated in the Indenture and those made part of the Indenture by reference to
the Trust Indenture Act of 1939 (15 U.S. Code ss.ss. 77aaa-77bbbb) as in effect
on the date of the Indenture or on the date of any amendment thereto, to the
extent required by Section 9.03 of the Indenture. Notwithstanding anything to
the contrary herein, the Securities are subject to all such terms, and Holders
are referred to the Indenture and such Act for a statement of such terms. The
Securities are general unsecured obligations of the Company limited to
$115,000,000 aggregate principal amount, except as otherwise provided in the
Indenture. Payment on each Security is guaranteed on a senior basis, jointly
and severally, by the Subsidiary Guarantors pursuant to Article Ten of the
Indenture.

5.       Optional Redemption.

         At any time or in part from time to time on and after August 15, 2002,
the Company may, at its option, redeem all or any portion of the Securities at
the redemption prices (expressed as percentages of the principal amount of the
Securities) set forth below, plus, in each case, accrued interest thereon to
the applicable redemption date, if redeemed during the 12-month period
beginning August 15 of the years indicated below:

<TABLE>
<CAPTION>
                    Year                      Percentage
                   <S>                         <C>
                    2002....................   104.875%
                    2003....................   103.250%
                    2004....................   101.625%
                    2005 and thereafter        100.000%
</TABLE>

         In addition, at any time or from time to time on or before August 15,
2000, up to $40,250,000 in aggregate principal amount of the Securities may be
redeemed, at the option of the Company, upon not less than 30 or more than 60
days' notice, from the Net Proceeds of a Public Equity Offering, at a price
equal to 109 3/4% of the principal amount thereof, together with accrued and
unpaid interest, if any, to the date of redemption, provided that at least
$74,750,000 in aggregate principal amount of the Securities remains outstanding
immediately after such redemption and that such redemption occurs within 60
days following the closing of such Public Equity Offering.

         In the case of any redemption of Securities, interest installments due
and payable on or prior to the date of redemption will be payable to Holders of
such Securities of record at the close of business on the relevant Record Date
referred to on the face hereof. Securities (or portions thereof) for whose
redemption and payment provision is made in accordance with the Indenture shall
cease to bear interest from and after the date of redemption. In the event of
redemption or purchase of this Series __ Security in part only, a new Series __
Security or Securities for the unredeemed or unpurchased portion hereof shall
be issued in the name of the Holder hereof upon the cancellation hereof.

         The Securities do not have the benefit of any sinking fund
obligations.



                                      A-4

<PAGE>   78
6.       Notice of Redemption.

         Notice of redemption will be mailed to the registered address of each
Holder of Securities to be redeemed at least 30 days but not more than 60 days
before the redemption date. If less than all Securities are to be redeemed, the
Trustee shall select pro rata, by lot or by any other method considered fair
and appropriate by the Trustee and, if the Securities are listed on any
securities exchange, by a method that complies with the requirements of such
exchange, the Securities to be redeemed in multiples of $1,000. Securities in
denominations larger than $1,000 may be redeemed in part.

7.       Change of Control.

         Upon the occurrence of a Change of Control, the Company shall be
obligated to make an offer to purchase all of the then outstanding Securities
(a "Change of Control Offer"), and shall purchase, on a Business Day (the
"Change of Control Purchase Date") not more than 60 nor less than 30 days
following the occurrence of a Change of Control, all of the then outstanding
Securities validly tendered pursuant to such Change of Control Offer, at a
purchase price (the "Change of Control Purchase Price") equal to 101% of the
principal amount thereof, plus accrued and unpaid interest, if any, to the
Change of Control Purchase Date. The Change of Control Offer is required to
remain open for at least 20 Business Days and until the close of business on
the fifth Business Day prior to the Change of Control Purchase Date.

         In order to effect such Change of Control Offer, the Company shall,
not later than the 30th day after the occurrence of such Change of Control,
mail to the Trustee and to each Holder of the Securities notice of the Change
of Control Offer, which notice shall govern the terms of the Change of Control
Offer and shall state, among other things, the procedures that Holders of the
Securities must follow to accept the Change of Control Offer.

8.       Asset Sale Offer.

         In the event of certain Asset Sales, the Company may be required to
make an Asset Sale Offer to purchase all or any portion of each Holder's
Securities, at 100% of the principal amount thereof plus accrued and unpaid
interest, if any, to the Asset Sale Offer Purchase Date.

9.       Restrictive Covenants.

         The Indenture imposes certain limitations on, among other things, the
ability of the Company or Subsidiaries to merge or consolidate with any other
Person or sell, lease or otherwise transfer all or substantially all of its
properties or assets, the ability of the Company or the Subsidiaries to dispose
of certain assets, to pay dividends and make certain other distributions and
payments, to make certain investments or redeem, retire, repurchase or acquire
for value shares of capital stock, to incur additional Indebtedness or incur
encumbrances against certain property, to engage in other business activities,
and to enter into certain transactions with Related Persons, all subject to
certain limitations described in the Indenture.

10.      Denominations, Transfer, Exchange.

         The Securities are in registered form without coupons in denominations
of $1,000 and whole multiples of $1,000. A Holder may transfer or exchange
Securities in accordance with the Indenture. The Registrar may require a
Holder, among other things, to furnish appropriate endorsements and transfer



                                      A-5

<PAGE>   79
documents and to pay any taxes and fees required by law or permit ted by the
Indenture. The Registrar need not transfer or exchange any Securities selected
for redemption. Also, it need not transfer or exchange any Securities for a
period of 30 days before a selection of Securities to be redeemed.

11.      Persons Deemed Owners.

         The registered Holder of a Security may be treated as the owner of it
for all purposes and neither the Company, the Trustee nor any Agent shall be
affected by notice to the contrary.

12.      Unclaimed Money.

         If money for the payment of principal or interest remains unclaimed
for one year, the Trustee or Paying Agent will pay the money back to the
Company at its request. After that, all liability of the Trustee and such
Paying Agents with respect to such money shall cease.

13.      Discharge and Defeasance.

         Subject to certain conditions, the Company at any time may terminate
some or all of its obligations under the Securities and the Indenture if the
Company deposits with the Trustee money or U.S. Government Obligations for the
payment of principal and interest on the Securities to redemption or maturity,
as the case may be.

14.      Amendment, Supplement, Waiver.

         Subject to certain exceptions, the Indenture or the Securities may be
amended or supplemented with the consent of the Holders of at least a majority
in principal amount of the Securities, and any past default or noncompliance
with any provision may be waived with the consent of the Holders of a majority
in principal amount of the Securities. Without the consent of any Holder, the
Company may amend or supplement the Indenture or the Securities to, among other
things, cure any ambiguity, defect or inconsistency or to provide for
uncertificated Securities in addition to, or in place of, certificated
Securities or to make any change that does not adversely affect the rights of
any Holder.

15.      Successor Corporation.

         When a successor corporation assumes all the obligations of its
predecessor under the Securities and the Indenture, the predecessor corporation
will be released from those obligations.

16.      Defaults and Remedies.

         An event of default generally is: default in payment of principal on
the Securities; default for 30 days in payment of interest on the Securities;
failure by the Company or any Subsidiary Guarantor for 45 days after notice to
comply with any of its other agreements in the Indenture; certain defaults
under or acceleration prior to maturity of other indebtedness; certain final
judgments against the Company or Subsidiaries; a failure of any Subsidiary
Guarantee of a Material Subsidiary to be in full force and effect or denial by
any Subsidiary Guarantor of its obligations with respect thereto; and certain
events of bankruptcy or insolvency. Subject to certain limitations in the
Indenture, if an Event of Default occurs and is continuing, the Trustee or the
Holders of at least 25% in principal amount of the then outstanding Securities
may declare all the Securities to be due and payable immediately, except that
in the case of an Event of Default arising from certain events of bankruptcy,
insolvency or reorganization relating to the 



                                      A-6

<PAGE>   80
Company or any Material Subsidiary, all outstanding Securities shall become due
and payable immediately without further action or notice. Holders may not
enforce the Indenture or the Securities except as provided in the Indenture.
The Trustee may require indemnity satisfactory to it before it enforces the
Indenture or the Securities. Subject to certain limitations, Holders of a
majority in principal amount of the Securities may direct the Trustee in its
exercise of any trust or power. The Company must furnish an annual compliance
certificate to the Trustee.

17.      Trustee Dealings with Company.

         U.S. Trust Company of Texas, N.A., the Trustee under the Indenture, in
its individual or any other capacity, may become the owner or pledgee of
Securities and may otherwise deal with the Company or its Subsidiaries or
Affiliates with the same rights it would have if it were not Trustee, subject,
however, to required actions on the part of the Trustee in the event it
acquires any conflicting interest.

18.      No Recourse Against Others.

         A DIRECTOR, OFFICER, EMPLOYEE OR STOCKHOLDER, AS SUCH, OF THE COMPANY,
ANY SUBSIDIARY GUARANTOR OR THE TRUSTEE, SHALL NOT HAVE ANY LIABILITY FOR ANY
OBLI GATIONS OF THE COMPANY, ANY SUBSIDIARY GUARANTOR OR THE TRUSTEE, UNDER THE
SECURITIES OR THE INDENTURE OR FOR ANY CLAIM BASED ON, IN RESPECT OF OR BY
REASON OF, SUCH OBLIGATIONS OR THEIR CREATION. EACH HOLDER BY ACCEPTING A
SECURITY WAIVES AND RELEASES ALL SUCH LIABILITY. THE WAIVER AND RELEASE ARE
PART OF THE CONSIDERATION FOR THE ISSUE OF THE SECURITIES AND THE SUBSIDIARY
GUARANTEES.

19.      Authentication.

         This Security shall not be valid until the Trustee or an
authenticating agent signs the certificate of authentication on the other side
of this Security.

20.      Abbreviations.

         Customary abbreviations may be used in the name of a Holder or an
assignee, such as: TEN COM (=tenants in common), TEN ENT (=tenants by the
entireties), JT TEN (=joint tenants with right of survivorship and not as
tenants in common), CUST (=Custodian), and U/G/M/A (=Uniform Gifts to Minors
Act).

21.      CUSIP Numbers.

         Pursuant to a recommendation promulgated by the Committee on Uniform
Security Identification Procedures, the Company will cause CUSIP numbers to be
printed on the Securities as a convenience to Holders. No representation is
made as to the accuracy of such numbers as printed on the Securities and
reliance may be placed only on the other identification numbers printed hereon.

         The Company will furnish to any Holder upon written request and 
without charge a copy of the Indenture. Requests may be made to: Secretary,
Dailey Petroleum Services Corp., One Lawrence Center, 2507 North Frazier,
Conroe, Texas 77305.



                                      A-7
<PAGE>   81
22.      Governing Law.

         THIS INDENTURE AND THE SECURITIES AND THE SUBSIDIARY GUARANTEES SHALL
BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW
YORK WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAWS TO THE
EXTENT THAT THE APPLICATION OF THE LAW OF ANOTHER JURISDICTION WOULD BE
REQUIRED THEREBY.

[If a Series A Security, the following:

23.      Exchange Option.

         At the option of the Holders hereof, the Series A Securities may be
exchanged, pursuant to the Registration Rights Agreement, for a like aggregate
principal amount of Series B Securities.]



                                      A-8

<PAGE>   82
                              [Form of Assignment]


To assign this Security, fill in the form below:

I or we assign and transfer this Security to:

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

                ----------------------------------------------
                  (Insert assignee's soc. sec. or tax ID no.)

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

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

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

-------------------------------------------------------------------------------
             (Print or type assignee's name, address and zip code)

and irrevocably appoint ________________________________________ agent to
transfer this Security on the books of the Company. The agent may substitute
another to act for him.






Your Signature:
                 --------------------------------------------------------------
                 (Sign exactly as your name appears on the other side of this 
                  Security)


Date:
       ------------------
Signature Guarantee:
                      ----------------




                                      A-9

<PAGE>   83
                  [Form of Option of Holder to Elect Purchase]


         If you want to elect to have this Security purchased by the Company
pursuant to Section 4.12 or Section 4.17 of the Indenture, check the
appropriate box:

                           Section 4.12     [   ]
                           Section 4.17     [   ]

         If you want to have only part of this Security purchased by the
Company pursuant to Section 4.12 or 4.17 of the Indenture, state the amount (in
integral multiples of $1,000):

$ 
 -----------------------------

Date:                              Signature:
      ----------------------------            ---------------------------------
                                             (Sign exactly as your name appears
                                             on the other side of this Security)


Signature Guarantee:
                     --------------------------



                                      A-10

<PAGE>   84
                                                                    EXHIBIT A-1


                         [Form of Notation on Security
                       Relating to Subsidiary Guarantee]

                              SUBSIDIARY GUARANTEE

         Subject to the limitations set forth in the Indenture, the Subsidiary
Guarantors (as defined in the Indenture referred to in the Security upon which
this notation is endorsed, and each hereinafter referred to as a "Subsidiary
Guarantor," which term includes any successor or additional Subsidiary
Guarantor under the Indenture) have unconditionally guaranteed (a) the due and
punctual payment of the principal of, premium (if any), and interest on the
Securities, whether at maturity, acceleration, redemption or otherwise, (b) the
due and punctual payment of interest on the overdue principal of and interest
on the Securities, if any, to the extent lawful, (c) the due and punctual
performance of all other obligations of the Company to the Holders or the
Trustee, all in accordance with the terms set forth in the Indenture, and (d)
in case of any extension of time of payment or renewal of any Securities or any
of such other obligations, the same will be promptly paid in full when due or
performed in accordance with the terms of the extension or renewal, whether at
stated maturity, by acceleration or otherwise. Capitalized terms used herein
have the meanings assigned to them in the Indenture unless otherwise indicated.

         No stockholder, officer, director or incorporator, as such, past,
present or future, of the Subsidiary Guarantors shall have any personal
liability under this Subsidiary Guarantee by reason of his or its status as
such stockholder, officer, director or incorporator.

         This Subsidiary Guarantee shall be binding upon each Subsidiary
Guarantor and its successors and assigns and shall inure to the benefit of the
successors and assigns of the Trustee and the Holders and, in the event of any
transfer or assignment of rights by any Holder or the Trustee, the rights and
privileges herein conferred upon that party shall automatically extend to and
be vested in such transferee or assignee, all subject to the terms and
conditions hereof and in the Indenture.

         This Subsidiary Guarantee shall not be valid or obligatory for any
purpose until the certificate of authentication on the Security upon which this
Subsidiary Guarantee is noted shall have been executed by the Trustee under the
Indenture by the manual signature of one of its authorized signatories.


                                    Subsidiary Guarantors:

                                    DAILEY INTERNATIONAL, INC., a Delaware
                                      corporation



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



                                    A-1 - 1

<PAGE>   85
                                    DAILEY INTERNATIONAL SALES CORPORATION,
                                      a Delaware corporation



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


                                    COLUMBIA PETROLEUM SERVICES CORP.,
                                     a Delaware corporation



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



                                    INTERNATIONAL PETROLEUM SERVICES, INC.,
                                     a Delaware corporation



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



                                    DAILEY ENVIRONMENTAL REMEDIATION
                                    TECHNOLOGIES, INC., a Texas corporation



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


                                    DAILEY WORLDWIDE SERVICES, CORP., a 
                                     Texas corporation



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



                                    A-1 - 2
<PAGE>   86

                                    AIR DRILLING INTERNATIONAL, INC., a
                                     Delaware corporation



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


                                    AIR DRILLING SERVICES, INC., a Wyoming
                                      corporation


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



                                    A-1 - 3

<PAGE>   87
                                                                   EXHIBIT A-2


                     [Form of Legend For Global Securities]


         Any Global Security authenticated and delivered hereunder shall bear a
legend in addition to the Private Placement Legend, if required pursuant to
Section 2.14, in substantially the following form:

                  THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE
         INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A
         DEPOSITORY OR A NOMINEE OF A DEPOSITORY OR A SUCCESSOR DEPOSITORY.
         THIS SECURITY IS NOT EXCHANGEABLE FOR SECURITIES REGISTERED IN THE
         NAME OF A PERSON OTHER THAN THE DEPOSITORY OR ITS NOMINEE EXCEPT IN
         THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE, AND NO TRANSFER
         OF THIS SECURITY (OTHER THAN A TRANSFER OF THIS SECURITY AS A WHOLE BY
         THE DEPOSITORY TO A NOMINEE OF THE DEPOSITORY OR BY A NOMINEE OF THE
         DEPOSITORY TO THE DEPOSITORY OR ANOTHER NOMINEE OF THE DEPOSITORY) MAY
         BE REGISTERED EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE
         INDENTURE.

                  UNLESS THIS SECURITY IS PRESENTED BY AN AUTHORIZED
         REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION
         ("DTC"), TO THE ISSUER OR ITS AGENT FOR REGISTRATION OF TRANSFER,
         EXCHANGE, OR PAYMENT, AND ANY SECURITY 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 INASMUCH AS THE
         REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.



                                    A-2 - 1

<PAGE>   88
                                                                    EXHIBIT A-3


                   CERTIFICATE TO BE DELIVERED UPON EXCHANGE
                   OR REGISTRATION OF TRANSFER OF SECURITIES

                Re:      9 3/4% Senior Notes due 2007, Series A, aNd
                         9 3/4% Senior Notes due 2007, Series B
                         (the "Securities"), of Dailey Petroleum Services Corp.

         This Certificate relates to $_______ principal amount of Securities
held in the form of *o a beneficial interest in a Global Security or *o
Physical Securities by _______________ (the "Transferor").

         The Transferor:*

         [ ] has requested by written order that the Registrar deliver in
exchange for its beneficial interest in the Global Security held by DTC a
Physical Security or Physical Securities in definitive, registered form of
authorized denominations and in an aggregate principal amount equal to its
beneficial interest in such Global Security (or the portion thereof indicated
above); or

         [ ] has requested that the Registrar by written order exchange or
register the transfer of a Physical Security or Physical Securities.

         In connection with such request and in respect of each such Security,
the Transferor does hereby certify that the Transferor is familiar with the
Indenture relating to the above captioned Securities and the restrictions on
transfers thereof as provided in Section 2.06 of such Indenture, and that the
transfer of these Securities does not require registration under the Securities
Act of 1933, as amended (the "Act") because *:

         [ ] Such Security is being acquired for the Transferor's own account,
without transfer (in satisfaction of subparagraph (a)(1) or (c)(1) of Section
2.06 of the Indenture).

         [ ] Such Security is being transferred to a "qualified institutional
buyer" (as defined in Rule 144A under the Act), in reliance on Rule 144A.

         [ ] Such Security is being transferred to an institutional "accredited
investor" (within the meaning of subparagraphs (a)(1), (2), (3) or (7) of Rule
501 under the Act).

         [ ] Such Security is being transferred in reliance on Regulation S 
under the Act.

         [ ] Such Security is being transferred in reliance on Rule 144 under 
the Act.



                                    A-3 - 1

<PAGE>   89
         [ ] Such Security is being transferred in reliance on and in compliance
with an exemption from the registration requirements of the Act other than Rule
144A or Rule 144 or Regulation S under the Act to a person other than an
institutional "accredited investor."


                                          [INSERT NAME OF TRANSFEROR]


                                          By:
                                               -------------------------------
                                                   [Authorized Signatory]

Date:

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


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

     *   Check applicable box.



                                    A-3 - 2

<PAGE>   90
                                                                   EXHIBIT A-4


                      FORM OF CERTIFICATE TO BE DELIVERED
                        IN CONNECTION WITH TRANSFERS TO
                       INSTITUTIONAL ACCREDITED INVESTORS


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


U.S. Trust Company of Texas, N.A.

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

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


         Re:      Dailey Petroleum Services Corp. Indenture (the "Indenture")
                  relating to 9 3/4% Senior Notes due 2007, Series A,
                  or 9 3/4% Senior Notes due 2007, Series B

Ladies and Gentlemen:

         In connection with our proposed purchase of 9 3/4% Senior Notes due
2007, Series A, or 9 3/4% Series Notes due 2007, Series B (the "Securities"),
of Dailey Petroleum Services Corp. (the "Company"), we confirm that:

         1. We have received such information as we deem necessary in order to 
make our decision.

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

         3. We understand that the offer and sale of the Securities have not
been registered under the Securities Act, and that the Securities may not be
offered or sold within the United States or to, or for the account or benefit
of, U.S. persons except as permitted in the following sentence. We agree, on
our own behalf and on behalf of any accounts for which we are acting as
hereinafter stated, that if we should sell any Securities, we will do so only
(A) to the Company or any subsidiary thereof, (B) inside the United States in
accordance with Rule 144A under the Securities Act to a "qualified
institutional buyer" (as defined therein), (C) inside the United States to an
institutional "accredited investor" (as defined below) that, prior to such
transfer, furnishes (or has furnished on its behalf by a U.S. broker-dealer) to
the Trustee a signed letter substantially in the form hereof, (D) outside the
United States in accordance with Regulation S under the Securities Act, (E)
pursuant to the exemption from registration provided by Rule 144 under the
Securities Act (if available), or (F) pursuant to an effective registration
statement under the Securities Act, and we further agree to provide to any
person purchasing Securities from us a notice advising such purchaser that
resales of the Securities are restricted as stated herein.

         4. We understand that, on any proposed resale of Securities, we will
be required to furnish to you and the Company, such certification, legal
opinions and other information as you and the Company



                                    A-4 - 1

<PAGE>   91
may reasonably require to confirm that the proposed sale complies with the
foregoing restrictions. We further understand that the Securities purchased by
us will bear a legend to the foregoing effect.

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

         6. We are acquiring the Securities purchased by us for our account or
for one or more accounts (each of which is an institutional "accredited
investor") as to each of which we exercise sole investment discretion, for
investment purposes and not with a view to, or for offer or sale in connection
with, any distribution in violation of the Securities Act.

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

                                     Very truly yours,

                                     [Name of Transferee]



                                     By:
                                          --------------------------
                                          [Authorized Signatory]



                                    A-4 - 2

<PAGE>   92
                                                                    EXHIBIT A-5


                           FORM OF CERTIFICATE TO BE
                            DELIVERED IN CONNECTION
                          WITH REGULATION S TRANSFERS


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


U.S. Trust Company of Texas, N.A.

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

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

         Re:      Dailey Petroleum Services Corp. ("the Company")
                  9 3/4% Senior Notes due 2007, Series A, and
                  9 3/4% Senior Notes due 2007, Series B (the "Securities")

Ladies and Gentlemen:

         In connection with our proposed sale of $__________ aggregate
principal amount of the Securities, we confirm that such sale has been effected
pursuant to and in accordance with Regulation S (as amended, "Regulation S")
under the Securities Act of 1933, as amended (the "Securities Act"), and,
accordingly, we represent that:

                  (1)  the offer of the Securities was not made to a person 
         in the United States or targeted at any identifiable group of U.S. 
         citizen abroad;

                  (2)  either (a) at the time the buy offer was originated, the
         transferee was outside the United States or we and any person acting
         on our behalf reasonably believed that the transferee was outside the
         United States, or (b) the transaction was executed in, on or through
         the facilities of a designated off-shore securities market and neither
         we nor any person acting on our behalf knows that the transaction has
         been prearranged with a buyer in the United States;

                  (3)  no directed selling efforts (as defined in Rule 902(b) of
         Regulation S) have been made in the United States in contravention of
         the requirements of Rule 904(b) of Regulation S;

                  (4)  the transaction is not part of a plan or scheme to evade 
         the registration requirements of the Securities Act; and

                  (5)  we have advised the transferee of the transfer 
         restrictions applicable to the Securities.




                                    A-5 - 1

<PAGE>   93
         You and the Company and your and their respective counsel are entitled
to rely upon this letter and are irrevocably authorized to produce this letter
or a copy thereof to any interested party in any administrative or legal
proceeding or official inquiry with respect to the matters covered hereby.
Defined terms used herein without definition have the respective meanings
provided in Regulation S.

                                       Very truly yours,


                                       [Name of Transferor]



                                        By:
                                             ---------------------------------
                                               [Authorized Signature]



                                   A-5 - 2