December 10, 1996                                                 $300,000.00
                                                        Los Altos, California

                          VISTA TECHNOLOGIES INC.
                        12% Secured Promissory Note
                             Due June 30, 1997
       (or Earlier Upon Completion of Certain Events defined herein)
                                     
THE SECURITIES REPRESENTED BY THIS NOTE HAVE NOT BEEN REGISTERED UNDER THE
UNITED STATES SECURITIES ACT OF 1933, AS AMENDED, OR QUALIFIED UNDER THE TRUST
INDENTURE ACT OF 1939, AS AMENDED (THE "ACTS").  ACCORDINGLY, NO TRANSFER OF
THIS NOTE OR ANY INTEREST HEREIN MAY BE MADE EXCEPT PURSUANT TO AN EFFECTIVE
REGISTRATION STATEMENT UNDER THE ACTS UNLESS THE ISSUER HAS RECEIVED A
SATISFACTORY OPINION OF COUNSEL THAT SUCH TRANSFER DOES NOT REQUIRE
REGISTRATION UNDER THE ACTS.


  VISTA TECHNOLOGIES INC., a Nevada corporation (herein called the
"Company"), for value received, hereby promises to pay to CASTLE ROCK PARTNERS
L.P., c/o 200 Park Avenue, Suite 3900, New York, NY 10166 (the "Payee"), or
order, at the principal office of the Company in the State of California not
later than on the 30th day of June, 1997 or within five (5) business days
after an Accelerating Event as defined below (the earliest of such dates being
herein called the "Maturity Date") the principal sum of THREE HUNDRED THOUSAND
DOLLARS ($300,000.00) in United States funds, together with interest on the
unpaid principal amount of this Bridge Note from the date hereof.

  1.    BRIDGE NOTES.   This note is one of a duly authorized issue of not
more than one million dollars ($1,000,000) in 12% Secured Promissory Notes
(herein called the "Bridge Notes") made by the Company and originally issued
by the Company pursuant to a private placement of securities in 1996.(1)   All
of the Bridge Notes are issuable substantially in the form of this Bridge
Note.

  2.    ACCELERATION OF MATURITY DATE.   The Maturity Date of this Bridge
Note shall be automatically accelerated, and all principal and interest on
this Bridge Note shall be immediately due and payable, of the fifth business
day after receipt by the Company of at least $5 million in gross proceeds as a
result of the sale of its Series A convertible preferred stock pursuant to
financing arrangements negotiated with Paramount Capital Incorporated.(2)

  3.    INTEREST.   Interest on the unpaid principal of this Bridge Note
from the date hereof shall be payable at the rate of twelve percent (12%) per
annum, interest payable in arrears on the Maturity Date of this Bridge Note
and to accrue until this Note is paid in full.   Interest shall also be
payable on any earlier date fixed for optional prepayment by the Company.

________________________
(1)     The total issue of the Bridge Notes was limited to an aggregate of
        $300,000.

(2)     Rights of acceleration due to sale of the Company's interest in shares
        of Technical Chemical and Products, Inc. was waived by separate letter
        agreement dated December 10, 1996.

<PAGE>
  4.    COLLATERAL SECURITY.    The principal and interest of the Bridge
Notes are secured by the pledge as collateral of all of the assets of the
Company pursuant to the terms of that certain Security Agreement dated
November 11, 1996 executed by the Company for the benefit of the holders of
the Bridge Notes, a copy of which has been delivered to the Payee by the
Company.

  5.    OPTIONAL PREPAYMENT.   The Company, at its option and without
prior notice, may at any time prepay all or any portion of the principal and
interest of the Bridge Notes at the time outstanding, in each case at the
principal amount so being prepaid plus all unpaid interest accrued thereon to
the date fixed for prepayment, without any premium or other penalty for such
prepayment.

  6.    INVESTMENT INTENT; RESTRICTIONS ON TRANSFER.   The Payee and any
other holder of this Bridge Note, by acceptance hereof, represents and
warrants that this Bridge Note has been acquired by said holder for its own
account for investment, and acknowledges that any proposed sale, assignment or
transfer of this Bridge Note is prohibited unless such sale, assignment or
transfer in the opinion of counsel for the Company will not require the prior
registration of this Bridge Note under the Securities Act of 1933, as amended,
or the qualification of this Bridge Note under the Trust Indenture Act of
1939, as amended.

  5.    DEFAULT AND ACCELERATION.   If one or more of the following events
(herein called "Events of Default") shall happen, that is to say:

(a)     If default be made in the punctual payment of the principal of, or
        interest on, this Bridge Note, as the same shall become due and payable,
        whether at the Maturity Date or a date fixed for optional or mandatory
        prepayment of this Bridge Note or any portion thereof in accordance with
        its terms, and such default shall continue for three (3) business days
        after the Company has received written notice of default from the
        registered holder of this Bridge Note; or

(b)     If (i) any court of competent jurisdiction shall enter a decree or order
        not vacated or stayed within 30 days from the date of entry thereof (A)
        appointing a trustee or receiver of the Company or of any substantial
        part of the property of the Company, or (B) approving a petition for, or
        effecting, an arrangement in bankruptcy of, or a reorganization pursuant
        to any bankruptcy act of, the Company, or any other judicial
        modification or alteration of the rights of the holders of this Bridge
        Note or of other creditors of the Company, or (ii) the Company shall
        itself file any such petition or take or consent to any other action
        seeking any such judicial order or shall make an assignment for the
        benefit of its creditors or shall admit in writing its inability to pay
        its debts generally as they become due.

then all of the unpaid principal and interest of this Bridge Note shall become
immediately due and payable upon demand made by the holder of this Bridge Note
if any one or more Events of Default shall occur and be continuing at the time
of such demand.


                                     2

<PAGE>
  6.    COSTS OF COLLECTION.   The Company covenants that, if default be
made in any payment of the principal of or interest on this Bridge Note, the
Company will pay the holder of this Bridge Note such further amount as shall
be sufficient to cover the costs and expenses of collection, including without
limitation reasonable attorneys' fees of such holder and all other costs
incurred for court filings, witnesses, preparation, prosecution and
enforcement of collection.

  7.    OTHER PROVISIONS.

  7.1.  This Bridge Note is issued upon the express condition, to which
the Payee and each successive holder expressly assents and by receiving the
same agrees, that no recourse under or upon any obligation, covenant or
agreement of this Bridge Note, or for the payment of the principal of or the
interest on, this Bridge Note, or for any claim based on this Bridge Note, or
otherwise in respect thereof, shall be had against any incorporator or any
past, present or future stockholder, officer or director, as such, of either
Company or of any successor corporation, whether by virtue of any
constitution, statute or rule of law, or by any assessment or penalty or
otherwise howsoever, all such individual liability being hereby expressly
waived and released as a condition of and as part of the consideration for the
execution and issue of this Bridge Note; provided, however, that nothing
herein shall prevent enforcement of the liability, if any, of any stockholder
or subscriber to capital stock upon or in respect of capital stock not fully
paid.

  7.2.  Any notice or demand which by any provision of this Bridge Note is
required or provided to be given or served to or upon the Company shall be
deemed to have been sufficiently given or served for all purposes by being
sent as registered or certified mail, postage prepaid, addressed to the
Company at its principal office in the State of California, marked for the
attention of its Chief Executive Officer.

  7.3.  No course of dealing between the Company and the holder of this
Bridge Note or any delay on the part of the holder in exercising any rights
under this Bridge Note shall operate as a waiver of any rights of any holder
of this Bridge Note.

  7.4.  This Bridge Note shall be governed by the laws of the State of
California.

  IN WITNESS WHEREOF, the Company has caused this Bridge Note to be signed
in its corporate name by an officer thereunder duly authorized, and to be
dated as of the day and year first above written.


                              VISTA TECHNOLOGIES INC.

  
                              By: /s/ Thomas A. Schultz
                                  ----------------------------
                                  Thomas A. Schultz, President

ATTEST:


/s/ William M. Curtis
----------------------------
William M. Curtis, Secretary



                                     3