EXHIBIT 5.1


                                January 22, 1999

                                                                  (202) 639-7315

Board of Directors
Neff Corp.
3750 N.W. 87th Avenue
Miami, Florida  33166

Gentlemen:

         We are acting as special counsel for Neff Corp., a Delaware corporation
(the "Company"), Neff Machinery, Inc., a Florida corporation ("Neff Machinery"),
Neff Rental, Inc., a Florida corporation ("Neff Rental"), Air Rental & Supply,
Inc., a Texas corporation ("Air Rental") and Neff Asset Management, Inc., a
Delaware corporation ("Neff Asset Management," and together with Neff Machinery,
Neff Rental and Air Rental, the "Guarantors"), in connection with the offer by
the Company to exchange up to $100,000,000 aggregate principal amount of the
Company's 10 1/4% Senior Subordinated Notes due 2008 (the "New Notes"), which
will be registered under the Securities Act of 1933, as amended (the "Securities
Act"), for a like principal amount at maturity of the Company's issued and
outstanding 10 1/4% Senior Subordinated Notes due 2008 (the "Old Notes," and
together with the New Notes, the "Notes") (the "Exchange Offer") pursuant to the
Registration Statement on Form S-4 filed on January 22, 1999, as amended (the
"Registration Statement") under the Securities Act. The Old Notes are, and the
New Notes will be, unconditionally guaranteed (the "Guarantees") by the
Guarantors.

         In connection with this opinion, we have (i) investigated such
questions of law, (ii) examined originals or certified, conformed or
reproduction copies of such agreements, instruments, documents and records of
each of the Company and the Guarantors, (iii) examined such certificates of
public officials, officers or other representatives of each of the Company and
the Guarantors, and other persons, and such other documents, and (iv) reviewed
such information from officers and representatives of each of the Company and
the Guarantors and others as we have deemed necessary or appropriate for the
purposes of this opinion.

         In all such examinations, we have assumed the legal capacity of all
natural persons executing documents (other than the capacity of officers of the
Company executing documents in such capacity), the genuineness of all signatures
on original or certified copies and the conformity to original or certified
documents of all copies submitted to us as conformed or reproduction copies. As
to various questions of fact relevant to the opinions expressed herein, we have
relied upon, and assumed the accuracy of, certificates and oral or written
statements and other information of or from public officials, officers or other
representatives of each of the Company and the Guarantors and other persons.


BOARD OF DIRECTORS
NEFF CORP.                                                                PAGE 2

         To the extent that it may be relevant to the opinion expressed herein,
we have assumed, for purposes of the opinions expressed herein, that (i) the
trustee for the Notes (the "Trustee") has the power and authority to enter into
and perform the indenture for the Notes (the "Indenture"), (ii) the Indenture
has been duly authorized, executed and delivered by the Trustee and is a valid
and binding obligation of the Trustee, enforceable against the Trustee in
accordance with its terms and (iii) the Notes have been duly authenticated and
delivered by the Trustee.

         Based upon the foregoing, and subject to the limitations,
qualifications and assumptions set forth herein, we are of the opinion that:

         1. The New Notes have been duly and validly authorized by the Company,
and when duly executed by the proper officers of the Company and issued in
exchange for the Old Notes as contemplated by the Registration Statement, will
constitute valid and legally binding obligations of the Company, entitled to the
benefits of the Indenture, and enforceable against the Company in accordance
with their terms.

         2. The Guarantees of the New Notes have been duly authorized and, when
the New Notes have been duly executed and the Guarantees have been duly executed
in accordance with the terms of the Indenture, will constitute valid and legally
binding obligations of the Guarantors, entitled to the benefits of the
Indenture, and enforceable against the Guarantors in accordance with their
terms.

         The enforceability and effectiveness of the provisions of the New Notes
and the Guarantees are limited by and subject to (i) applicable bankruptcy,
fraudulent conveyance, insolvency, reorganization, moratorium or other similar
laws now or hereafter in effect affecting creditors' rights generally and (ii)
general principles of equity (including, without limitation, standards of
materiality, good faith, fair dealing and reasonableness) whether such
principles are considered in a proceeding at law or in equity.

         The opinions set forth above are subject to the following
qualifications:

         (A) The opinions expressed herein are limited to the federal laws of
the United States and the laws of the State of New York and, to the extent
relevant hereto, the General Corporation Law of the State of Delaware. We assume
no obligations to supplement this letter if any applicable laws change after the
date hereof or if we become aware of any facts that might change the opinions
expressed herein after the date hereof.

         (B) Provisions in the Guarantees that provide that the Guarantors'
liability thereunder shall not be affected by actions or failures to act on the
part of the recipient of the Guarantees or by amendments or waivers of
provisions of documents governing the guaranteed obligations might not be
enforceable under circumstances in which such actions, failures to act,
amendments or waivers so radically change the essential nature of the terms and
conditions of the guaranteed obligations that, in effect, a new contract has
arisen between such recipient and the primary obligor on whose behalf any
Guarantor may have the rights and remedies of a "debtor" under the UCC. We have
assumed that sufficient valid consideration has been received by each Guarantor
for entry into the Guarantee.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to this firm under the caption
"Legal Matters" in the prospectus forming a part of the Registration Statement.
In giving this consent, we do not hereby admit that we are in the category of
persons whose consent is required under Section 7 of the Securities Act.

                            FRIED, FRANK, HARRIS, SHRIVER & JACOBSON

                            By: /s/ STEPHEN I. GLOVER
                                -----------------------------------------
                                   Stephen I. Glover