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                                    GUARANTY

                               GUARANTY AGREEMENT
                             (Twenty Holdings, Inc.)

         This GUARANTY AGREEMENT (this "Guaranty"), dated effective as of
December 14, 2000, is executed and delivered by TWENTY HOLDINGS, INC., a
Delaware corporation ("Guarantor"), to and in favor of EXPORT DEVELOPMENT
CORPORATION, as administrative agent for itself and the other Lenders (as such
term is hereinafter defined) (in such capacity, together with its successors and
assigns in such capacity, "Administrative Agent").

                                   WITNESSETH:

         A. Alamosa PCS, Inc. ("Borrower"), Alamosa PCS Holdings, Inc.
("Holdings"), Texas Telecommunications, LP, Alamosa Wisconsin Limited
Partnership, Alamosa Finance, LLC, Alamosa Limited, LLC, Alamosa Wisconsin GP,
LLC, Alamosa Delaware GP, LLC, the lenders named therein (together with their
successors and assigns, "Lenders") and Administrative Agent entered into that
certain Second Amended and Restated Credit Agreement dated as of June 23, 2000
(as the same may be amended, renewed, extended, restated, replaced, substituted,
supplemented or otherwise modified from time to time, the "Credit Agreement")
and, in connection therewith, the Borrower executed and delivered (a) that
certain Tranche A Note dated June 23, 2000, in the original principal amount of
$116,900,000 payable to the order of Export Development Corporation, (b) that
certain Tranche B Note dated June 23, 2000, in the original principal amount of
$40,600,000 payable to the order of Export Development Corporation and (c) that
certain Tranche C Note dated June 23, 2000, in the original principal amount of
$17,500,000 payable to the order of Export Development Corporation, (such
promissory notes, as they may be amended, renewed, extended, restated, replaced,
substituted, supplemented or otherwise modified from time to time, are
hereinafter individually called a "Note" and collectively called the "Notes";
the Credit Agreement, the Notes, the Security Documents and the other Loan
Documents (as such terms are defined in the Credit Agreement), including,
without limitation, any and all security agreements, pledge agreements,
assignments, guaranties, licenses, lien waivers, collection account agreements
and other agreements, documents, instruments and certificates now or hereafter
executed and/or delivered in connection therewith, and any and all amendments,
modifications, renewals, extensions, restatements and/or supplements thereto
from time to time, are hereinafter collectively called the "Loan Documents").

         B. Borrower is a wholly-owned Subsidiary of Holdings and Holdings is a
wholly-owned Subsidiary of Guarantor and Guarantor has directly and indirectly
benefitted and will directly and indirectly benefit fiom the Loans evidenced and
governed by the Credit Agreement, the Notes and the other Loan Documents and the
other transactions evidenced by and contemplated in the Loan Documents.

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         NOW, THEREFORE, for good and valuable consideration, the receipt and
adequacy of which are hereby acknowledged, Guarantor hereby agrees as follows:

         1. Definitions. Unless otherwise defined in this Guaranty, all
capitalized terms used in this Guaranty shall have the meanings ascribed to such
terms in the Credit Agreement.

         2. Guaranty of Indebtedness. Liabilities and Obligations. Guarantor
hereby absolutely, unconditionally and irrevocably guarantees (a) payment and
performance to Administrative Agent and Lenders, as and when the same become due
or performable strictly in accordance with the terms and provisions of the Loan
Documents, whether at stated maturity, by acceleration or otherwise, of any and
all Obligations (as such term is defined in the Credit Agreement), which
Obligations include, without limitation, (i) any and all interest, penalties,
fees and expenses (specifically including, but not limited to, attorneys' fees
and expenses) which Borrower may now or at any time hereafter owe to
Administrative Agent or any Lender (whether or not such interest, penalties,
fees and expenses were originally contracted with Administrative Agent or any
Lender or with another or others and whether or not such interest, penalties,
fees and expenses are enforceable against Borrower) pursuant to the Credit
Agreement, any Note or any other Loan Document plus (ii) the principal amount of
any and all indebtedness, liabilities and other obligations, whether primary,
absolute, secondary, direct, indirect, fixed, contingent, liquidated,
unliquidated, secured or unsecured, matured or unmatured, joint, several or
joint and several, due or to become due and whether arising by agreement, note,
discount, acceptance, overdraft or otherwise, which Borrower may now or at any
time hereafter owe to Administrative Agent or any Lender (whether or not such
indebtedness, liabilities and obligations were originally contracted with
Administrative Agent or any Lender or with another or others and whether or not
such indebtedness, liabilities or obligations are enforceable against Borrower)
pursuant to the Credit Agreement, any Note or any other Loan Document and (b)
the faithful prompt and complete compliance by Borrower and the other Loan
Parties with all terms, conditions, covenants, agreements and undertakings of
Borrower and the other Loan Parties (or any one or more of them) under the
Credit Agreement, any Note or any other Loan Document (the Obligations and the
interest, penalties, fees, expenses, indebtedness, liabilities and obligations,
etc. referred to in clauses (a) and (b) preceding as to which payment,
performance and compliance are guaranteed pursuant to this Guaranty are
hereinafter individually and collectively called the "Guaranteed Obligations").

         Notwithstanding that Borrower may not be liable or obligated to
Administrative Agent or any Lender for interest and/or attorneys' fees and
expenses on, or in connection with, the Guaranteed Obligations from and after
the Petition Date (as hereinafter defined) as a result of the provisions of the
federal bankruptcy laws or otherwise, the Guaranteed Obligations for which
Guarantor shall be liable and obligated under this Guaranty shall include (to
the extent permitted by law or a court of competent jurisdiction) interest
accruing on the Guaranteed Obligations at the highest rate provided for in the
Credit Agreement from and after the date on which Borrower files for protection
under the federal bankruptcy laws or from and after the date on which an
involuntary proceeding is filed against Borrower under the federal bankruptcy
laws (herein

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collectively referred to as the "Petition Date") and all attorneys' fees and
expenses incurred by Administrative Agent or any Lender from and after the
Petition Date in connection with the Guaranteed Obligations.

         3. Continuing Guaranty of Payment. This Guaranty is and shall be an
absolute, unconditional, irrevocable and continuing guaranty of payment, and not
merely of collection, and from time to time or at any time the Guaranteed
Obligations may be increased, reduced or paid in full without affecting the
liability or obligation of Guarantor with respect to indebtedness, liabilities
and obligations of Borrower to Administrative Agent or any Lender thereafter
incurred. Guarantor further agrees that this Guaranty shall continue to be
effective or be reinstated (if a release or discharge has occurred), as the case
may be, if at any time any payment (or any part thereof) to Administrative Agent
or any Lender in respect of the Guaranteed Obligations is rescinded or must
otherwise be restored by Administrative Agent or any Lender pursuant to any
bankruptcy, insolvency, reorganization, receivership or other debtor relief
granted to Borrower or its successors or assigns. In the event that
Administrative Agent or any Lender must rescind or restore any payment received
by Administrative Agent or any Lender, respectively, in satisfaction of the
Guaranteed Obligations, as set forth herein, any prior release or discharge from
the terms of this Guaranty given to Guarantor by Administrative Agent or such
Lender, respectively, shall be without effect, and this Guaranty shall remain in
full force and effect. It is the intention of Administrative Agent, Lenders and
Guarantor that Guarantor's liabilities and obligations hereunder shall not be
discharged except by the full and complete payment and performance of the
Guaranteed Obligations and then only to the extent of such payment and
performance. Subject to Paragraph 21 hereof, this Guaranty is independent of,
and in addition and without modification to (except as expressly provided in
Paragraph 21 hereof), and does not impair or in any way affect any other
guaranty, endorsement or other agreement executed in favor of Administrative
Agent or any Lender, and this Guaranty and Guarantor's liabilities and
obligations under this Guaranty shall not be impaired or otherwise affected by
the execution, delivery or performance by Guarantor or any other Person of any
other guaranty, endorsement or other agreement.

         4. Absolute Guaranty. Guarantor's liabilities and obligations under
this Guaranty shall be absolute and unconditional irrespective of, shall not be
released, impaired, limited, reduced, conditioned upon or otherwise affected by
and shall continue in full force and effect notwithstanding the occurrence of
any event (other than an event consisting of payment and performance of such
liabilities and obligations as provided in Paragraph 3 hereof) at any time or
from time to time, including, without limitation, any one or more of the
following events specified in clauses (a) through (o) of this Paragraph 4 below,
and neither Administrative Agent nor any Lender shall be obligated or required
to take or to refrain from taking any of such actions or inactions specified
below and shall not have any liability, obligation or duty whatsoever with
respect to such actions or inactions, it being acknowledged and agreed by
Guarantor that all of such liabilities, obligations and duties (if any) of
Administrative Agent or any Lender otherwise existing and all rights and
remedies (if any) of Guarantor with respect thereto (whether such liabilities,
obligations, duties, rights or remedies exist by virtue of agreement, common
law, equity, statute or otherwise), and each and every defense which, under

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principles of guaranty or suretyship law, would otherwise operate to eliminate,
impair, condition or restrict any indebtedness, liability or obligation of
Guarantor for payment of the Guaranteed Obligations or otherwise under this
Guaranty is hereby expressly waived by Guarantor, including, without limitation,
any defense consisting of or based upon any one or more of the following matters
specified in clauses (a) through (o) of this Paragraph 4 below:

              (a) the taking or accepting of any security or other guaranty for
         any or all of the Guaranteed Obligations, whether heretofore,
         concurrently herewith or hereafter;

              (b) any failure to create or perfect or properly create or perfect
         any lien, security interest or assignment intended as security, or any
         release, surrender, exchange, substitution, subordination or loss of
         any security or guaranty at any time existing in connection with any or
         all of the Guaranteed Obligations for any reason; or any suretyship
         defenses, including, without limitation, any impairment of collateral;

              (c) any partial or full release of the liability or obligation of
         Guarantor under any other guaranty whether or not similar to this
         Guaranty;

              (d) the entering into, delivery of, modification of, amendment to
         or waiver of compliance with the Credit Agreement, any Note or any
         other Loan Document, or any agreement, document or instrument
         evidencing, securing or otherwise affecting all or part of the
         Guaranteed Obligations, without the notification of Guarantor, the
         right of such notification being hereby specifically waived by
         Guarantor;

              (e) the bankruptcy, insolvency, arrangement, adjustment,
         composition, liquidation, disability, dissolution or lack of authority
         (whether corporate, partnership or trust or relating to any other
         entity or Person) of Borrower, Guarantor or any other Loan Party or
         other Person at any time liable or obligated for the payment of any or
         all of the Guaranteed Obligations, whether now existing or hereafter
         arising;

              (f) any increase, reduction, renewal, extension, amendment,
         modification, repayment, refunding and/or rearrangement of the payment
         or any other terms or provisions of any or all of the Guaranteed
         Obligations at any time and from time to time, whether on one or more
         occasions, either with or without notice to or consent of Guarantor, or
         any adjustment, indulgence, forbearance or compromise that might be
         granted or given by Administrative Agent or any Lender to Borrower,
         Guarantor or any other Loan Party;

              (g) any neglect, delay, omission, failure or refusal of
         Administrative Agent or any Lender (i) to exercise or properly or
         diligently exercise any right or remedy with respect to any or all of
         the Guaranteed Obligations or the collection thereof or any collateral,
         security or guaranty therefor, whether under the Credit Agreement, any
         Note or any other Loan Document or otherwise, including, without
         limitation, to ensure compliance with any term or provision of the
         Credit Agreement or any other Loan

                                        4
<PAGE>

         Document, (ii) to take or prosecute or properly or diligently take
         or prosecute any action for the collection of any or all of the
         Guaranteed Obligations against Borrower, Guarantor or any other
         guarantor of any or all of the Guaranteed Obligations and/or any other
         Loan Party or Person, (iii) to foreclose or prosecute or properly or
         diligently foreclose or prosecute any action in connection with any
         agreement, document or instrument or arrangement evidencing, securing
         or otherwise affecting all or any part of the Guaranteed Obligations,
         including, without limitation, any failure to conduct a commercially
         reasonable foreclosure sale, or (iv) to mitigate damages or take any
         other action to reduce, collect or enforce the Guaranteed Obligations;

              (h) any failure of Administrative Agent or any Lender to give
         notice to Borrower, Guarantor and/or any other Loan Party of, or obtain
         the consent of Borrower, Guarantor and/or any other Loan Party with
         respect to, (i) the incurrence of any of the Guaranteed Obligations,
         (ii) the occurrence of any "Default" or "Event of Default" as such
         terms are defined in the Credit Agreement or any of the other Loan
         Documents, (iii) demand, presentment, protest, nonpayment, intention to
         accelerate, acceleration, lack of diligence or delay in collection of
         all or any part of the Guaranteed Obligations or any other matter, or
         the absence thereof, (iv) any renewal, extension or assignment of the
         Guaranteed Obligations or any part thereof, (v) the disposition or
         release of all or any part of any security for the Guaranteed
         Obligations (whether or not such disposition is commercially
         reasonable) or (vi) any other action taken or refrained from being
         taken by Administrative Agent or any Lender against Borrower or any
         other Loan Party, it being agreed that (except as may be expressly
         provided in the other Loan Documents) neither Administrative Agent nor
         any Lender shall be required to give Borrower, Guarantor or any other
         Loan Party any notice of any kind or to obtain Borrower's, Guarantor's
         or any other Loan Party's consent under any circumstances whatsoever
         with respect to or in connection with the Guaranteed Obligations;

              (i) the unenforceability, illegality or uncollectibility of all or
         any part of the Guaranteed Obligations against Borrower or any other
         Loan Party by reason of (i) failure of consideration, (ii) breach of
         warranty, (iii) fraud, (iv) the fact that the interest contracted for,
         charged, collected or received in respect of the Guaranteed Obligations
         exceeds the amount permitted by law, (v) the act of creating the
         Guaranteed Obligations or any part thereof is ultra vires, (vi) the
         officers, directors, partners, trustees or representatives creating the
         Guaranteed Obligations acted in excess of their authority or lacked
         legal capacity, (vii) the Credit Agreement, any Note or any other Loan
         Document evidencing the Guaranteed Obligations has been forged or
         otherwise is irregular or is not genuine or authentic, (viii)
         expiration of the applicable statute of limitations of the Guaranteed
         Obligations, (ix) failure to comply with the statute of frauds, (x)
         lender liability, or (xi) accord and satisfaction;

              (j) any payment by Borrower or any other Loan Party to
         Administrative Agent or any Lender is held to constitute a preferential
         transfer or a fraudulent conveyance or transfer under any applicable
         law, or for any reason Administrative Agent

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<PAGE>

         or any Lender is required to refund such payment or pay such
         amount to Borrower or any other Loan Party or any other Person;

              (k) any merger, reorganization, consolidation or dissolution of
         Borrower or any other Loan Party, any sale, lease or transfer of any or
         all of the assets of Borrower or any other Loan Party, or any change in
         name, business, location, composition, structure or any change in the
         shareholders, partners or members (whether by accession, secession,
         death, dissolution, transfer of assets or otherwise) of Borrower or any
         other Loan Party;

              (1) any failure of Administrative Agent or any Lender to notify
         Guarantor of (i) the acceptance of this Guaranty, (ii) the making of
         Loans by any Lender in reliance on this Guaranty, (iii) the failure of
         Borrower or any other Loan Party to make any payment due by Borrower or
         any other Loan Party to Administrative Agent or any Lender, or (iv) any
         information regarding the financial condition or prospects of Borrower
         or any other Loan Party;

              (m) any existing or future offset, claim or defense of Borrower or
         any other Loan Party against Administrative Agent or any Lender or
         against payment of all or any part of the Guaranteed Obligations,
         whether such offset, claim or defense arises in connection with the
         Guaranteed Obligations (or the transactions creating the Guaranteed
         Obligations) or otherwise;

              (n) any full or partial release of the liability of Borrower or
         any other Loan Party, any guarantor of all or any part of the
         Guaranteed Obligations or any other Person for all or any part of the
         Guaranteed Obligations, it being acknowledged and agreed by Guarantor
         that it may be required to pay the Guaranteed Obligations in full
         without assistance or support, whether from Borrower or any other Loan
         Party, any other guarantor or any other Person; or

              (o) any other action taken or omitted to be taken with respect to
         any of the Credit Agreement, any Note or any other Loan Document, the
         Guaranteed Obligations or the security and collateral therefor, whether
         or not such action or omission prejudices Guarantor or increases the
         likelihood that Guarantor will be required to pay all or any part of
         the Guaranteed Obligations pursuant to the terms hereof.

The parties intend the preceding waiver of suretyship defenses to have the
effects described in Section 48 of the Restatement (Third) of the Law of
Suretyship and Guaranty. Without limiting the foregoing or Guarantor's liability
under this Guaranty, to the extent that Administrative Agent and Lenders (or any
of them) have advanced funds or extended credit to Borrower and do not receive
payments or benefits thereon in the amounts and at the times required or
provided by or in connection with the Credit Agreement, any Note or any other
Loan Document, Guarantor is absolutely liable to make such payments and to
confer such benefits on Lenders on a timely basis.

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<PAGE>

         5. Representations and Warranties. In connection with this Guaranty,
Guarantor hereby represents and warrants to Administrative Agent and Lenders
that:

              (a) Guarantor, Borrower and the other Loan Parties are members of
         an affiliated and integrated group of business entities and are engaged
         in related businesses and supporting lines of business; Guarantor has
         received and will receive a direct and indirect material benefit from
         the transactions evidenced by and contemplated in the Credit Agreement,
         the Notes and the other Loan Documents; this Guaranty is given by
         Guarantor in furtherance of the direct and indirect business interests
         and corporate purposes of Guarantor, and is necessary to the conduct,
         promotion and attainment of the businesses of Borrower and Guarantor;
         and the value of the consideration received and to be received by
         Guarantor is reasonably worth at least as much as the liability and
         obligation of Guarantor hereunder,

              (b) The execution and delivery of this Guaranty and the
         performance of and compliance with the terms hereof will not constitute
         a default (or an event which with notice or lapse of time or both would
         constitute a default) under, or result in the breach of, any material
         contract, agreement or instrument to which Guarantor is a party or
         which may be applicable to Guarantor or any of its assets;

              (c) This Guaranty, when executed and delivered by Guarantor, will
         constitute the legal, valid and binding obligation of Guarantor
         enforceable in accordance with its terms, except as limited by
         bankruptcy, insolvency or other laws of general application relating to
         the enforcement of creditors' rights and general principles of equity;

              (d) As of the date of this Guaranty, and after giving effect to
         this Guaranty and the contingent obligation evidenced by this Guaranty,
         Guarantor is not, on either an unconsolidated basis or a consolidated
         basis with Borrower and Guarantor's other Subsidiaries, insolvent, as
         such term is used or defined in any applicable bankruptcy, fraudulent
         conveyance, fraudulent transfer or similar law, and Guarantor has and
         will have assets which, fairly valued, exceed its indebtedness,
         liabilities and obligations; Guarantor is not executing this Guaranty
         with any intention to hinder, delay or defraud any present or future
         creditor or creditors of Guarantor; Guarantor is not engaged in any
         business or transaction (including, without limitation, the execution
         of this Guaranty) which will leave Guarantor with unreasonably small
         capital or assets which are unreasonably small in relation to the
         business or transactions engaged in by Guarantor, and Guarantor does
         not intend to engage in any such business or transaction; Guarantor
         does not intend to incur, nor does Guarantor believe that it will
         incur, debts beyond Guarantor's ability to repay such debts as they
         mature;

              (e) All acts and conditions required to be performed and satisfied
         prior to the creation and issuance of this Guaranty, and to constitute
         this Guaranty as the legal, valid and binding obligation of Guarantor
         in accordance with its terms, have been performed and satisfied in due
         and strict compliance with all applicable laws;

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<PAGE>

              (f) Guarantor is familiar with, and has independently received
         books and records regarding, the financial condition of Borrower and is
         familiar with the value of any and all collateral (if any) intended to
         secure the Guaranteed Obligations; however, Guarantor is not relying on
         such financial condition or any such collateral (if any) as an
         inducement to enter into this Guaranty; Guarantor has adequate means to
         obtain from Borrower, on a continuing basis, the information referred
         to in this clause (f) preceding and is not relying on Administrative
         Agent or any Lender to provide any such information at any time;

              (g) Guarantor has not been induced to enter into this Guaranty on
         the basis of a contemplation, belief, understanding or agreement that
         any Person other than Guarantor will be liable to pay the Guaranteed
         Obligations;

              (h) Except for the execution of the Credit Agreement, neither
         Administrative Agent, any Lender nor any other Person has made any
         representation, warranty or statement to, or promise, covenant or
         agreement with, Guarantor in order to induce Guarantor to execute this
         Guaranty;

              (i) Borrower is a wholly-owned Subsidiary of Holdings which is a
         wholly-owned Subsidiary of the Guarantor; and

              (j) All representations and warranties in the Credit Agreement
         relating to the Guarantor are true and correct in all respects as of
         the date hereof, except to the extent made only as of a specific prior
         date, and on each date the representations and warranties thereunder
         are restated pursuant to any of the Loan Documents with the same force
         and effect as if such representations and warranties had been made on
         and as of such date, all of which are incorporated herein by reference.

         6. Default. Upon the occurrence and during the continuation of an Event
of Default, Guarantor shall, on demand by Administrative Agent and without
further demand and without notice of dishonor and without notice of any kind
(including, without limitation, notice of acceptance by Administrative Agent or
any Lender of this Guaranty) having been given to Borrower, Guarantor or any
other Person previous to such demand, promptly (i.e., not later than 1:00 p.m.,
New York, New York time; on the date of such demand or, if such demand is made
after 12:00 noon, New York, New York time, on the next succeeding Business Day)
pay, in immediately available funds, the full unpaid amount of the Guaranteed
Obligations, or such lesser amount, if any, as may be specifically demanded by
Administrative Agent from time to time, to Administrative Agent at
Administrative Agent's Principal Office located in Ottawa, Ontario Canada or at
such other place as Administrative Agent may specify to Guarantor in writing. If
acceleration of the time for payment of any amount payable by Borrower under or
with respect to any of the Guaranteed Obligations is stayed or otherwise delayed
upon the insolvency, bankruptcy or reorganization of Borrower, all such amounts
otherwise subject to acceleration under the terms of the Guaranteed Obligations
shall nonetheless be payable by Guarantor hereunder promptly on demand by
Administrative Agent.

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         7. Cumulative Remedies: No Election. If Guarantor is or becomes liable
or obligated for the Guaranteed Obligations, by endorsement or otherwise, other
than under this Guaranty, such liability or obligation shall not be in any
manner impaired or affected hereby, and the rights and remedies of
Administrative Agent or any Lender hereunder shall be cumulative of any and all
other rights and remedies that Administrative Agent or such Lender may ever have
against Guarantor. The exercise by Administrative Agent or any Lender of any
right or remedy hereunder or under any other agreement, document or instrument,
or at law or in equity, shall not preclude the concurrent or subsequent exercise
of any other right or remedy. Without in any way limiting the generality of the
foregoing, it is specifically understood and agreed that this Guaranty is given
by Guarantor as an additional guaranty or security to any and all other
guaranties or security heretofore, concurrently herewith or hereafter executed
and/or delivered by Guarantor to or in favor of Administrative Agent or any
Lender relating to the Guaranteed Obligations, and nothing herein shall ever be
deemed to in any way negate or replace any such other guaranties or security;
provided, however, that Administrative Agent and Lenders shall have all of their
rights and remedies under this Guaranty irrespective of anything to the contrary
contained in any such other guaranties or security. This Guaranty may be
enforced from time to time as often as occasion therefor may arise, and it is
agreed and understood that it shall not be necessary for Administrative Agent or
any Lender, in order to enforce this Guaranty against Guarantor, first to
exercise any rights or remedies against Borrower or any other Person or
institute suit or exhaust any available rights or remedies against security in
Administrative Agent's or any Lender's possession or under Administrative
Agent's or any Lender's control, or to resort to any other sources or means of
obtaining payment of the Guaranteed Obligations.

         8. Joint and Several Obligation. Guarantor agrees that Administrative
Agent and Lenders, in their sole discretion, may (a) bring suit against all
guarantors or other Persons liable or obligated to Administrative Agent or any
Lender or against any one or more of them, for interest, penalties, expenses,
fees, indebtedness, liabilities and obligations owed to Administrative Agent or
any Lender and apply any amounts obtained by Administrative Agent or any Lender
in such a manner as Administrative Agent or any Lender may elect, (b) bring suit
against all guarantors of the Guaranteed Obligations jointly and severally or
against any one or more of them, (c) settle fully or in part with any one or
more of such guarantors for such consideration as Administrative Agent or any
Lender may deem proper, and (d) partially or fully release one or more of such
guarantors from liability under any guaranty agreement, and that no such action
shall impair the rights of Administrative Agent or any Lender to collect the
Guaranteed Obligations (or the unpaid balance thereof) from other guarantors
(including, without limitation, Guarantor), or any of them, not so sued, settled
with or released.

         9. Release of Collateral, etc. If all or any part of the Guaranteed
Obligations is at any time secured, Guarantor agrees that Administrative Agent
or any Lender may, at any time and from time to time in its discretion and with
or without valuable consideration, allow substitution or withdrawal of
collateral or other security and release collateral or other security without
impairing or diminishing the liabilities or obligations of Guarantor hereunder.
Guarantor further agrees that, if Borrower or any other Person executes in favor
of Administrative Agent or any Lender any collateral agreement, mortgage, deed
of trust, collateral

                                        9
<PAGE>

assignment, security agreement or other security instrument, the exercise by
Administrative Agent or any Lender of any right or remedy thereby conferred on
Administrative Agent or any Lender shall be wholly discretionary with
Administrative Agent and such Lender, respectively, and that the exercise or
failure to exercise any such right or remedy shall in no way impair or diminish
the obligation of Guarantor hereunder. Guarantor further agrees that (except to
the extent prohibited by applicable law notwithstanding an agreement of the
parties to the contrary) neither Administrative Agent nor any Lender shall be
liable for its failure to use diligence or care in the collection of the
Guaranteed Obligations, in the creation or perfection of any lien, security
interest or assignment intended as security or in preserving the liability of
any Person liable or obligated on the Guaranteed Obligations, and Guarantor
hereby waives presentment for payment, notice of nonpayment, protest and notice
thereof, and diligence in bringing suit against any Person liable on the
Guaranteed Obligations or any part thereof.

         10. Binding Effect. This Guaranty is for the benefit of Administrative
Agent and Lenders and their successors and permitted assigns, and in the event
of an assignment by Administrative Agent or any Lender or its successors or
assigns of the Guaranteed Obligations, or any part thereof, the rights and
benefits hereunder, to the extent applicable to the indebtedness, liabilities
and obligations so assigned, may be transferred with such indebtedness,
liabilities and obligations. This Guaranty is binding, not only upon Guarantor,
but upon its successors and assigns.

         11. WAIVER OF SUBROGATION. CONTRIBUTION AND OTHER RIGHTS. UPON PAYMENT
BY GUARANTOR OF ANY SUMS IN RESPECT OF THE GUARANTEED OBLIGATIONS HEREUNDER
(INCLUDING, WITHOUT LIMITATION, ANY AMOUNTS ADVANCED TO BORROWER BY GUARANTOR),
ALL RIGHTS OF GUARANTOR AGAINST BORROWER OR ANY OTHER GUARANTOR OF THE
GUARANTEED OBLIGATIONS ARISING AS A RESULT THEREFROM BY WAY OF RIGHT OF
SUBROGATION, REIMBURSEMENT, EXONERATION, CONTRIBUTION, INDEMNIFICATION AND/OR
OTHERWISE SHALL IN ALL RESPECTS BE SUBORDINATE AND JUNIOR IN RIGHT OF PAYMENT
AND ENFORCEMENT TO THE PRIOR INDEFEASIBLE PAYMENT AND ENFORCEMENT IN FULL OF THE
GUARANTEED OBLIGATIONS. GUARANTOR SHALL NOT HAVE, AND HEREBY IRREVOCABLY WAIVES,
ANY AND ALL RIGHTS AND REMEDIES OF SUBROGATION, REIMBURSEMENT, EXONERATION,
CONTRIBUTION, INDEMNIFICATION AND/OR OTHERWISE AGAINST OR FROM BORROWER UNLESS
AND UNTIL ALL OF THE GUARANTEED OBLIGATIONS HAVE BEEN IRREVOCABLY PAID AND
PERFORMED IN FULL. IN ADDITION TO THE FOREGOING, GUARANTOR HEREBY IRREVOCABLY
WAIVES ANY AND ALL CLAIMS OR OTHER RIGHTS AND REMEDIES IT MAY NOW HAVE OR
HEREAFTER ACQUIRE AGAINST ADMINISTRATIVE AGENT, ANY LENDER, BORROWER OR ANY
OTHER PERSON UNDER CHAPTER 34 OF THE TEXAS BUSINESS AND COMMERCE CODE, UNDER
RULES 31 AND 163 OF THE TEXAS RULES OF CIVIL PROCEDURE, UNDER SECTION 17.001 OF
THE TEXAS CIVIL PRACTICE AND REMEDIES CODE AND

                                       10
<PAGE>

UNDER ANY OTHER STATUTE OF ANY STATE OR OTHER JURISDICTION REQUIRING RECOURSE
AGAINST THE PRIMARY OBLIGOR OR IMPOSING OTHER REQUIREMENTS AS A CONDITION TO
RECOURSE AGAINST A GUARANTOR IF AND TO THE EXTENT THAT THE SAME MAY BE
APPLICABLE TO THIS GUARANTY. Except as expressly otherwise provided in this
Paragraph 11, Guarantor shall have all rights of subrogation, reimbursement,
exoneration, contribution and indemnification that may exist under currently
applicable law.

         12. Subordination of Indebtedness and Liens. In connection with this
Guaranty, Guarantor hereby agrees that:

              (a) The payment of any and all principal of and interest on the
         Subordinated Indebtedness (as defined below) shall in all respects be
         subordinate and junior in right of payment and enforcement to the prior
         payment and enforcement in full of all Guaranteed Obligations as
         provided in this Paragraph 12. The Subordinated Indebtedness shall not
         be payable, and no payment of principal, interest or other amounts on
         account thereof, and no property or guaranty of any nature to secure,
         guarantee or pay the Subordinated Indebtedness shall be made or given,
         directly or indirectly by or on behalf of any Debtor (hereafter
         defined) or received, accepted, retained or applied by Guarantor unless
         and until the Guaranteed Obligations shall have been paid and performed
         in full; except that, prior to the occurrence and continuance of an
         Event of Default, Guarantor shall have the right to receive regularly
         scheduled payments, but not prepayments, on the Subordinated
         Indebtedness made in the ordinary course of business. After the
         occurrence and during the continuance of an Event of Default, no
         payments of principal or interest may be made or given, directly or
         indirectly, by or on behalf of any Debtor or received, accepted,
         retained or applied by Guarantor unless and until the Guaranteed
         Obligations shall have been paid and performed in full. If any sums
         shall be paid to Guarantor or any Affiliate of Guarantor by any Debtor
         or any other Person on account of the Subordinated Indebtedness when
         such payment is not permitted hereunder, such sums shall be held in
         trust by Guarantor for the benefit of Administrative Agent and Lenders
         and shall forthwith be delivered to Administrative Agent without
         affecting the liability of Guarantor under this Guaranty and may be
         applied by Administrative Agent against the Guaranteed Obligations in
         accordance with the Credit Agreement. Upon the request of
         Administrative Agent, Guarantor shall execute, deliver, and endorse to
         Administrative Agent such documentation as Administrative Agent may
         request to perfect, preserve and enforce its rights hereunder. For
         purposes of this Guaranty and with respect to Guarantor, the term
         "Subordinated Indebtedness" means all indebtedness, liabilities and
         obligations of Borrower or any Loan Party other than Guarantor
         (Borrower and such Loan Parties are hereinafter called the "Debtors")
         to Guarantor, whether such indebtedness, liabilities and obligations
         now exist or are hereafter incurred or arise, or are primary, absolute,
         secondary, direct, indirect, fixed, contingent, liquidated,
         unliquidated, secured or unsecured, matured or unmatured, joint,
         several, joint and several, or otherwise, and irrespective of whether
         such indebtedness, liabilities or obligations are evidenced by a note,
         contract, open account or otherwise, and irrespective of the Person

                                       11
<PAGE>

         or Persons in whose favor such indebtedness, obligations or
         liabilities may, at their inception, have been, or may hereafter be
         created, or the manner in which they have been or may hereafter be
         acquired by Guarantor.

              (b) Any and all Liens (including any judgment Liens) upon any
         Debtor's property or assets securing payment of any Subordinated
         Indebtedness (the "Subordinated Liens") shall be and remain inferior
         and subordinate to any and all Liens upon any Debtor's assets securing
         payment of the Guaranteed Obligations or any part thereof, regardless
         of whether such Subordinated Liens presently exist or are hereafter
         created or when such Subordinated Liens were created, perfected, filed
         or recorded. Guarantor shall not exercise or enforce any creditors'
         rights or remedies that it may have against any Debtor or foreclose,
         repossess, sequester or otherwise institute any action or proceeding
         (whether judicial or otherwise, including, without limitation, the
         commencement of, or joinder in, any bankruptcy, insolvency,
         reorganization, liquidation, receivership or other debtor relief law)
         to enforce any Subordinated Lien on any property or assets of any
         Debtor unless and until the Guaranteed Obligations shall have been
         irrevocably paid and performed in full;

              (c) In the event of any receivership, bankruptcy, reorganization,
         rearrangement, debtor's relief or other insolvency proceeding involving
         any Debtor as debtor, Administrative Agent shall have the right to
         prove and vote any claim under the Subordinated Indebtedness and to
         receive directly from the receiver, trustee or other court custodian
         all dividends, distributions and payments made in respect of the
         Subordinated Indebtedness until the Guaranteed Obligations have been
         paid in full. Administrative Agent may apply any such dividends,
         distributions and payments against the Guaranteed Obligations in
         accordance with the Credit Agreement;

              (d) All promissory notes, accounts receivable, ledgers, records or
         any other evidence of Subordinated Indebtedness, and all mortgages,
         deeds of trust, security agreements, assignments and other security
         documents evidencing the Subordinated Liens, shall contain a specific
         written notice thereon that the indebtedness and Liens evidenced
         thereby are subordinated under the terms of this Guaranty; and

              (e) The terms and provisions of this Paragraph 12 are given by
         Guarantor as additional rights, remedies and benefits to any and all
         other subordination agreements heretofore, concurrently herewith or
         hereafter executed by Guarantor to or in favor of Administrative Agent
         or any Lender, and nothing in this Guaranty shall ever be deemed to in
         any way negate or replace any other such previous, concurrent or
         subsequent subordination agreements.

         13. Right of Setoff. Guarantor hereby grants to Administrative Agent
and each Lender a right of setoff upon any and all monies, securities or other
property of Guarantor, and the proceeds therefrom, now or hereafter held or
received by or in transit to Administrative Agent or any Lender from or for the
account of Guarantor, whether for safekeeping, custody,

                                       12
<PAGE>

pledge, transmission, collection or otherwise, and also upon any and all
deposits (general or special) and credits of Guarantor, and any and all claims
of Guarantor against Administrative Agent or any Lender at any time existing.
The right of setoff granted pursuant to this Paragraph 13 shall be cumulative of
and in addition to Administrative Agent's and each Lender's common law right of
setoff.

         14. Further Assurances. Upon the request of Administrative Agent or any
Lender, Guarantor will, at any time and from time to time, duly execute and
deliver to Administrative Agent any and all such further agreements, documents
and instruments, and supply such additional information, as may be necessary or
advisable, in the reasonable opinion of Administrative Agent or any Lender, to
obtain the full benefits of this Guaranty.

         15. Invalid Provisions. If any provision of this Guaranty is held to be
illegal, invalid or unenforceable under present or future laws effective during
the tern hereof, such provision shall be fully severable, this Guaranty shall be
construed and enforced as if such illegal, invalid or unenforceable provision
had never comprised a part hereof, and the remaining provisions hereof shall
remain in full force and effect and shall not be affected by the illegal,
invalid or unenforceable provision or by its severance herefrom. Furthermore, in
lieu of such illegal, invalid or unenforceable provision there shall be added
automatically as a part of this Guaranty a provision as similar in terms to such
illegal, invalid or unenforceable provision as may be possible and be legal,
valid and enforceable. No provision herein or in any other Loan Document
evidencing the Guaranteed Obligations shall require the payment or permit the
collection of interest in excess of the maximum permitted by applicable law.

         16. Modification in Writing. No modification, consent, amendment or
waiver of any provision of this Guaranty, and no consent to any departure by
Guarantor herefrom, shall be effective unless the same shall be in writing and
signed by a duly authorized officer of Administrative Agent and Guarantor and
then shall be effective only in the specific instance and for the specific
purpose for which given.

         17. No Waiver. Etc. No notice to or demand on Guarantor or
Administrative Agent in any case shall entitle Guarantor or Administrative
Agent, respectively, to any other or further notice or demand in similar or
other circumstances. No delay or omission by Administrative Agent or any Lender
in exercising any right or remedy hereunder shall impair any such right or
remedy or be construed as a waiver thereof or any acquiescence therein, and no
single or partial exercise of any such right or remedy shall preclude other or
further exercise thereof or the exercise of any other right or remedy hereunder.

         18. Cumulative Rights. All rights and remedies of Administrative Agent
and Lenders hereunder are cumulative of each other and of every other right or
remedy which Administrative Agent or any Lender may otherwise have at law or in
equity or under any other contract or document, and the exercise of one or more
rights or remedies shall not prejudice or impair the concurrent or subsequent
exercise of other rights or remedies.

                                       13
<PAGE>

         19. Expenses. Guarantor agrees to pay on demand by Administrative Agent
all costs and expenses incurred by Administrative Agent or any Lender in
connection with the enforcement of the terms and provisions of this Guaranty
and, if and to the extent that Borrower is obligated therefor in accordance with
the Credit Agreement, any and all amendments, modifications, renewals,
restatements and/or supplements hereto from time to time, including, without
limitation, the reasonable fees and expenses of legal counsel to Administrative
Agent. If Guarantor should breach or fail to perform any provision of this
Guaranty, Guarantor agrees to pay to Administrative Agent all costs and expenses
incurred by Administrative Agent or any Lender in the enforcement of this
Guaranty from time to time, including, without limitation, the reasonable fees
and expenses of all legal counsel to Administrative Agent and Lenders.

         20. APPLICABLE LAW. THIS GUARANTY SHALL BE GOVERNED BY, AND CONSTRUED
IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK (WITHOUT REGARD TO
CONFLICTS OF LAWS PRINCIPLES).

         21. NO ORAL AGREEMENTS. THIS GUARANTY REPRESENTS THE FINAL AGREEMENT
BETWEEN GUARANTOR AND ADMINISTRATIVE AGENT AND LENDERS RELATING TO THE SUBJECT
MATTER OF THIS GUARANTY AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF SUCH PARTIES. THERE ARE NO
UNWRITTEN ORAL AGREEMENTS BETWEEN OR AMONG GUARANTOR AND ADMINISTRATIVE AGENT OR
ANY LENDER. THIS GUARANTY SUPERSEDES ALL PRIOR (IF ANY) ORAL AGREEMENTS, ORAL
ARRANGEMENTS OR ORAL UNDERSTANDINGS RELATING TO THE SUBJECT MATTER OF THIS
GUARANTY, AND THIS GUARANTY SUPERSEDES ALL PRIOR (IF ANY) WRITTEN AGREEMENTS
RELATING TO THE SUBJECT MATTER OF THIS GUARANTY IF AND TO THE EXTENT THAT SUCH
PRIOR AGREEMENTS ARE INCONSISTENT WITH THIS GUARANTY.

         22. Notices. All notices and other communications provided for in this
Guaranty and the other Loan Documents to which Guarantor is a party shall be
given or made by telecopy or in writing and telecopied, mailed by certified mail
return receipt requested or delivered to the intended recipient at the "Address
for Notices" specified below its name on the signature pages hereof, or, as to
any party, at such other address as shall be designated by such party in a
notice to each other party given in accordance with this Paragraph 22. Except as
otherwise provided in this Guaranty, all such communications shall be deemed to
have been duly given when transmitted by telecopy or personally delivered or, in
the case of a mailed notice, upon receipt, in each case given or addressed as
aforesaid; provided, however, that notices to Administrative Agent shall be
deemed given when received by Administrative Agent.

         23. Survival. All representations, warranties, covenants and agreements
of Guarantor in this Guaranty shall survive the execution of this Guaranty.

                                       14
<PAGE>

         24. Counterparts. This Guaranty may be executed in any number of
counterparts, each of which shall constitute an original, but all of which when
taken together shall constitute one and the same Guaranty.

         25. Limitation on Interest. Notwithstanding anything to the contrary
contained or referred to in this Guaranty, none of the terms and provisions of
this Guaranty, the Credit Agreement, the Notes or any other Loan Document shall
ever be construed to create a contract or obligation to pay interest at a rate
in excess of the Maximum Rate, and neither Administrative Agent nor any Lender
shall ever charge, receive, take, collect, reserve or apply, as interest on the
Obligations or the Guaranteed Obligations, any amount in excess of the Maximum
Rate. The parties hereto agree that any interest, charge, fee, expense or other
indebtedness, liability or obligation provided for in this Guaranty, the Credit
Agreement, the Notes or any other Loan Document which constitutes interest under
applicable law shall be, ipso facto and under any and all circumstances, limited
or reduced to an amount equal to the lesser of (a) the amount of such interest,
charge, fee, expense or other indebtedness liability or obligation that would
be payable in the absence of this Paragraph 25 or (b) an amount, which when
added to all other interest payable under this Guaranty, the Credit Agreement,
the Notes and any other Loan Document, equals the Maximum Rate. If,
notwithstanding the foregoing, Administrative Agent or any Lender ever contracts
for, charges, receives, takes, collects, reserves or applies as interest any
amount in excess of the Maximum Rate, such amount which would be deemed
excessive interest shall be deemed a partial payment or prepayment of principal
of the Obligations and the Guaranteed Obligations and treated hereunder as such,
and if the Obligations and the Guaranteed Obligations, or applicable portions
thereof, are paid in full, any remaining excess shall promptly be paid to
Borrower, Guarantor or such other Person (as appropriate). In determining
whether the interest paid or payable, under any specific contingency exceeds
the Maximum Rate, Guarantor, Borrower, Administrative Agent and Lenders shall,
to the maximum extent permitted by applicable law, (i) characterize any
nonprincipal payment as an expense, fee or premium rather than as interest, (ii)
exclude voluntary prepayments and the effects thereof, and (iii) amortize,
prorate, allocate and spread in equal or unequal parts the total amount of
interest throughout the entire contemplated term of the Obligations and the
Guaranteed Obligations, or applicable portions thereof, so that the interest
rate does not exceed the Maximum Rate at any time during the term of the
Obligations and the Guaranteed Obligations; provided that, if the unpaid
principal balance is paid and performed in full prior to the end of the full
contemplated term thereof, and if the interest received for the actual period of
existence thereof exceeds the Maximum Rate, Administrative Agent and Lenders
shall refund to Borrower, Guarantor or such other Person (as appropriate) the
amount of such excess and, in such event, neither Administrative Agent nor any
Lender shall be subject to any penalties provided by any laws for contracting
for, charging, receiving, taking, collecting, receiving or applying interest in
excess of the Maximum Rate.

         26. Irrevocable Nature of Guaranty. This Guaranty may not be revoked by
Guarantor; provided, however, in the event it shall be determined that Guarantor
shall have the right, in accordance with applicable law and notwithstanding its
express agreement herein to the contrary, to revoke this Guaranty, Guarantor may
deliver to Administrative Agent, at its address

                                       15
<PAGE>

for notices set forth herein, written notice of Guarantor's intention not to be
liable hereunder for any Guaranteed Obligations arising, created or incurred
after the effective date of Administrative Agent's receipt of such notice,
whereupon such notice shall be effective to the extent (but only to the extent)
provided hereinbelow as to Guarantor from and after (but not before) ten
Business Days after the date upon which such notice is actually delivered to and
received by and receipted for in writing by Administrative Agent (the "Effective
Revocation Time"); provided, further, however, that such notice shall not be
effective as to, and shall not in any way restrict, limit, impair, release or
otherwise affect, the indebtedness, liabilities or obligations of Guarantor
under this Guaranty with respect to (a) any Guaranteed Obligations consisting of
indebtedness, liabilities or obligations under the Credit Agreement, the Notes
or any other Loan Document, whether incurred before or after the Effective
Revocation Time (including, without limitation, any loans, advances or
extensions of credit at any time made or created under the Credit Agreement,
whether or not agreed, committed or contemplated to be made by Administrative
Agent or any Lender and whether or not discretionary with Administrative Agent
or any Lender), (b) any Guaranteed Obligations arising, created or incurred
prior to the Effective Revocation Time, (c) any amendments, modifications,
renewals, extensions, restatements and/or supplements to or of the indebtedness,
liabilities or obligations referred to in clauses (a) and (b) and preceding,
whether occurring before or after the Effective Revocation Time, or (d) any
interest or costs of collection with respect to any of the indebtedness,
liabilities or obligations referred to in clauses (a), (b), or (c) preceding.
Any revocation or attempted revocation of this Guaranty, whether in whole or in
part, shall not be effective except under the limited circumstances (if any),
and to the limited extent, expressly provided in this Paragraph 26.

         27. Reinstatement of Guaranteed Obligations. Notwithstanding anything
to the contrary contained in this Guaranty or any other Loan Document, if the
payment of any amount of principal of, interest with respect to or any other
amount constituting the Guaranteed Obligations, or any portion thereof, is
rescinded, voided or must otherwise be refunded by the Administrative Agent or
any Lender or otherwise for any reason whatsoever, then the Guaranteed
Obligations and all terms and provisions of this Guaranty will be automatically
reinstated and become automatically effective and in full force and effect, all
to the extent that and as though such payment so rescinded, voided or otherwise
refunded had never been made.

         28. Covenants and Agreements. Guarantor hereby covenants and agrees
that, as long as the Guaranteed Obligations or any part thereof are outstanding
or any Lender has any Commitment under the Credit Agreement, Guarantor shall,
and Guarantor shall cause each of its Subsidiaries to, comply, strictly in
accordance with the terms thereof, with all covenants and agreements
specifically applicable to it as set forth in any one or more of the Credit
Agreement and the other Loan Documents, all of which are hereby incorporated
herein by reference as if stated verbatim herein.

         29. Representations and Warranties. Guarantor hereby represents and
warrants to Administrative Agent and Lenders that all representations and
warranties applicable to Guarantor and/or its Subsidiaries as set forth in any
one or more of the Credit Agreement and the

                                       16
<PAGE>

other Loan Documents are true and correct in all respects and are hereby
incorporated herein by reference as if stated verbatim herein.

                                       17
<PAGE>

         IN WITNESS WHEREOF, the undersigned has executed this Guaranty as of
the date first written above.

                                       GUARANTOR
                                       ---------

                                       TWENTY HOLDINGS, INC.

                                       By: /s/ David Sharbutt
                                          --------------------------------------
                                       Name: David Sharbutt
                                            ------------------------------------
                                       Title: President
                                             -----------------------------------

                                       Address for Notices:
                                       --------------------

                                       5225 South Loop 289
                                       Lubbock, Texas 79424
                                       Attention: David Sharbutt
                                       Telephone: (806) 722-1100
                                       Telecopy:  (806) 722-1127

                                       Copy To:
                                       -------

                                       Jack McCutchin, Jr., Esq.
                                       Crenshaw, Dupree & Milam, L.L.P.
                                       1500 Broadway, 10th Floor
                                       Lubbock, Texas 79401
                                       Telephone: (806) 741-8436
                                       Telecopy:  (806) 762-3510

<PAGE>

         The undersigned has executed this Guaranty solely for the purpose of
confirming receipt and acceptance of this Guaranty and reliance on this Guaranty
by Administrative Agent and Lenders as of the date first written above.

                                       EXPORT DEVELOPMENT CORPORATION,
                                       as Administrative Agent


                                       By: /s/ Robert Kelly
                                          --------------------------------------
                                       Name: Robert Kelly
                                            ------------------------------------
                                       Title: Financial Services Manager
                                             -----------------------------------

                                       By: /s/ Stephen Davies
                                          --------------------------------------
                                       Name: Stephen Davies
                                            ------------------------------------
                                       Title: Financial Services Manager
                                             -----------------------------------

                                       Address for Notices:
                                       --------------------
                                       151 O'Connor Street
                                       Ottawa, Ontario, Canada K1A 1K3
                                       Attention: Loan Operations
                                                  reference: 880-USA-8957
                                       Telecopy No.:  (613) 598-2514
                                       Telephone No.: (613) 598-2500