[Letterhead of Whitman Breed Abbott & Morgan]


                                               May 15, 1996


NAI Technologies Inc.
2405 Trade Centre Avenue
Longmont, Colorado  80503-7602

                Re:  Securities of NAI Technologies, Inc.

Gentlemen:

           We refer to the Registration Statement on Form S-1 (the "Registration
Statement") under the Securities Act of 1933, as amended (the "Securities Act"),
filed by NAI Technologies Inc., a New York corporation (the "Company"), with the
Securities  and  Exchange  Commission  (the   "Commission").   The  Registration
Statement  covers an aggregate of up to (i) $8,342,000  principal  amount of 12%
Convertible  Subordinated Promissory Notes due 2001 (the "Notes") of the Company
by the holders  thereof (the  "Noteholders"),  (ii) Warrants to Purchase  Common
Stock  (the   "Warrants")   of  the   Company  by  the  holders   thereof   (the
"Warrantholders"),  and (iii) an aggregate of 8,904,336 shares (the "Shares") of
common stock, par value $.10 per share (the "Common  Stock"),  of the Company by
the holders thereof (the "Shareholders"),  consisting of (1) 4,171,000 shares of
Common  Stock  which  may be  issued  upon  the  conversion  of the  Notes  (the
"Noteholders' Shares"), (2) 4,119,700 shares of Common Stock which may be issued
upon the exercise of the Warrants (the  "Warrantholders'  Shares"),  (3) 250,000
shares of Common Stock of the Company  previously issued to The Bank of New York
and Chemical  Bank (the "Bank  Lenders")  pursuant to that  certain  Amended and
Restated Credit  Agreement,  dated as of April 12, 1995, as amended to date (the
"Credit Agreement"),  by and between the Company and the Bank Lenders (the "Bank
Lenders'  Shares"),  and (4)  363,636  shares  of  Common  Stock of the  Company
previously issued to Active Investors II Ltd. ("Active  Investors")  pursuant to
that certain Common Stock Purchase Agreement,  dated as of November 3, 1994 (the
"Stock Purchase  Agreement"),  by and between the Company and Active  ("Active's
Shares").

           We are attorneys admitted to practice in the State of New York and we
are not, and do not purport to be, experts in the law of any other  jurisdiction
other than  Federal  law.  The  opinions  set forth in this  opinion  letter are
limited to the law of the State of New York and Federal law.

           We have examined the original, or a photostatic or certified copy, of
such records of the Company,  certificates  of public  officials  and such other
documents as we have deemed  relevant and necessary as the basis for the opinion
set forth below.  In such  examination,  we have assumed the  genuineness of all
signatures,  the authenticity of all documents submitted to us as originals, the
conformity to original  documents of all documents  submitted to us as certified
or photostatic copies and the authenticity of the originals of such copies.

           Based upon our examination  mentioned above,  subject the assumptions
stated and relying on statements of fact contained in the documents that we have
examined, we are of the opinion that (i) the Notes issued and










sold by the Company to the Noteholders were duly authorized for issuance and are
validly  issued  and  are  binding obligations of the Company, (ii) the Warrants
issued and sold by the Company to the  Warrantholders  were duly authorized  for
issuance  and  are  validly  issued, (iii) the  Noteholders'  Shares  were  duly
authorized for issuance and are presently reserved for issuance upon  conversion
of the Notes and upon issuance in accordance with  the  terms  thereof  will  be
validly issued, fully paid and non-assessable,  (iv) the Warrantholders'  Shares
were duly authorized for issuance and are  presently  reserved for issuance upon
exercise  of the Warrants and upon issuance in accordance with the terms thereof
will  be validly issued, fully paid and non-assessable,  (v) the  Bank  Lenders'
Shares were duly authorized for issuance and are validly issued, fully paid  and
non-assessable  and (vi) Active's Shares  were  duly authorized for issuance and
are validly issued, fully paid and non-assessable.

           We  consent  to  the  filing  of this  opinion  as an  Exhibit to the
Registration Statement.  In giving  this  consent,  we do not admit  that we are
within the category of persons whose consent is required under section  7 of the
Securities Act or the General Rules and Regulations of the Commission.

                                              Very truly yours,

                                              WHITMAN BREED ABBOTT & MORGAN