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                        [United Rentals Letterhead]


                                          December 29, 2000



Ronald F. Carapezzi
President and General Manager
General Electric Capital Corporation
Commercial Equipment Financing
401 Merritt Seven, Second Floor
Norwalk, CT 06856

Santos Fund I, L.P.
3155 NW 77 Avenue
Miami, FL 33122

Jorge Mas, Jose Ramon Mas and Juan Carlos Mas
3155 NW 77 Avenue
Miami, FL 33122


Dear Sirs:

      United Rentals, Inc. ("United Rentals") is pleased to submit to
General Electric Capital Corporation ("GE Capital"), Santos Fund I, L.P.
("Santos") and certain members of the Mas family (the "Mas Family") this
letter to pursue a transaction described in a proposal letter of even date,
the form of which is attached hereto (the "Proposal Letter"), from United
Rentals to the Special Committee (the "Special Committee") of the Board of
Directors of Neff Corp. ("Neff"). If you each agree to pursue the
transaction, United Rentals will submit the Proposal Letter to the Special
Committee. We have no intention of proceeding with any proposal to Neff
with respect to the transaction contemplated by the Proposal Letter and the
attached term sheet (the "Term Sheet") without the approval of each of you.
Capitalized terms used herein shall have the meanings set forth in the
Proposal Letter and the Term Sheet.

      By signing this letter, the parties hereto confirm their support and
approval of the transactions described in this letter, the Proposal Letter
and the Term Sheet and that (i) after the closing, GE Capital and Santos
would own 6 million shares of Neff Class B common stock, (ii) a group of
investors including GE Capital would purchase $90 million of United Rentals
Series C Perpetual Convertible Preferred Stock ("Series C Preferred
Stock"), and (iii) the members of the Mas Family would exchange their Neff
shares for shares of Series C Preferred Stock, as more fully described in
the Proposal Letter.

      The proposed transaction is contingent, among other things, upon the
approval of the Neff Special Committee, the respective Boards of Directors
of United Rentals and Neff, United Rentals' senior lenders, Neff
stockholders, and appropriate regulatory agencies. The proposed transaction
is also contingent on completion of satisfactory due diligence (including
branch due diligence after receiving full access and cooperation by Neff),
the signing of a definitive merger agreement and the satisfaction of its
terms and conditions, confirmation prior to the signing of a definitive
merger agreement that the proposed transaction would not negatively change
United Rentals' current credit ratings, and acceptance of United Rentals'
exchange offer by holders of at least 95% of the Old Notes. There can be no
assurance that these conditions will be met or that this transaction will
take place.

      This letter, including the attached Proposal Letter and the Term
Sheet, constitutes a non-binding agreement in principle regarding a
transaction on the general terms and conditions outlined herein and in the
Proposal Letter and the Term Sheet. The Proposal Letter and the Term Sheet
do not purport to summarize all of the terms and conditions upon which any
transaction would be based, which terms and conditions would be contained
fully only in any final documentation, and indicate only the principal
terms and conditions under which an overall transaction would be
considered. Each party may for whatever reason or for no reason change the
terms of its participation in the proposed transaction, or cease further
consideration of any transaction, at any time without liability to any
party, and no party shall have any claim that any other party did not act
in good faith.

      The parties will need to make appropriate public filings disclosing
this letter in order to comply with their obligations under the federal
securities laws. Wherever reasonably possible, the parties will coordinate
their public disclosures.

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      If you should have any questions regarding this letter, the Proposed
Letter or the Term Sheet, I can be reached at (203) 622-3131. Questions of
a legal nature should be directed to our legal counsel, Richard Grossman of
Skadden, Arps, Slate, Meagher & Flom LLP at (212) 735-2116.

      This letter may be executed in any number of counterparts, each of
which shall be an original, but all of which together shall constitute one
instrument.

                                          Very truly yours,


                                          /s/ John Milne
                                          John Milne


Agreed and accepted:

General Electric Capital Corporation

By: /s/ Ronald F. Carapezzi     Date: 12/29/00
   -------------------------
Name:  Ronald F. Carapezzi
Title: Vice President


Santos Fund I, L.P.

By: /s/ Jorge Mas               Date: 12/29/00
   --------------------------
Name:  Jorge Mas
Title:


/s/ Jorge Mas                   Date: 12/29/00
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Jorge Mas


/s/ Jose Ramon Mas               Date: 12/29/00
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Jose Ramon Mas


/s/ Juan Carlos Mas              Date: 12/29/00
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Juan Carlos Mas