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                                                                     Exhibit 4.3



THIS WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE OF THIS WARRANT HAVE NOT
BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES
ACT"), AND MAY NOT BE SOLD, OFFERED FOR SALE, ASSIGNED, TRANSFERRED OR OTHERWISE
DISPOSED OF, UNLESS REGISTERED PURSUANT TO THE PROVISIONS OF THE SECURITIES ACT
OR AN OPINION OF COUNSEL IS OBTAINED STATING THAT SUCH DISPOSITION IS IN
COMPLIANCE WITH AN AVAILABLE EXEMPTION FROM SUCH REGISTRATION.


MAY ___, 2000



                             MANSUR INDUSTRIES INC.


              (INCORPORATED UNDER THE LAWS OF THE STATE OF FLORIDA)


               WARRANT FOR THE PURCHASE OF SHARES OF COMMON STOCK

NO. WRT-_____


         FOR VALUE RECEIVED, MANSUR INDUSTRIES INC., a Florida corporation (the
"Company"), hereby certifies that _____________________ or assigns (the
"Holder") is entitled, subject to the provisions of this Warrant, to purchase
from the Company, up to ________________________ (___________) fully paid and
non-assessable shares of Common Stock at a price of $5.50 per share (the
"Exercise Price").

         The term "Common Stock" means the Common Stock, par value $.001 per
share, of the Company as constituted on May ___, 2000 (the "Base Date"). The
number of shares of Common Stock to be received upon the exercise of this
Warrant may be adjusted from time to time as hereinafter set forth. The shares
of Common Stock deliverable upon such exercise, and as adjusted from time to
time, are hereinafter referred to as "Warrant Stock." The term "Other
Securities" means any other equity or debt securities that may be issued by the
Company in addition thereto or in substitution for the Warrant Stock in
accordance with the terms hereof. The term "Company" means and includes the
corporation named above as well as (i) any immediate or more remote successor
corporation resulting from the merger or consolidation of such corporation (or
any immediate or more remote successor corporation of such corporation) with
another corporation, or (ii) any corporation to which such corporation (or any
immediate or more remote successor corporation of such corporation) has
transferred its property or assets as an entirety or substantially as an
entirety.


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         Upon receipt by the Company of evidence reasonably satisfactory to it
of the loss, theft, destruction or mutilation of this Warrant, and (in the case
of loss, theft or destruction) of reasonably satisfactory indemnification, and
upon surrender and cancellation of this Warrant, if mutilated, the Company shall
execute and deliver a new Warrant of like tenor and date. Any such new Warrant
executed and delivered shall constitute an additional contractual obligation on
the part of the Company, whether or not this Warrant so lost, stolen, destroyed
or mutilated shall be at any time enforceable by anyone.

         The Holder agrees with the Company that this Warrant is issued, and all
the rights hereunder shall be held subject to, all of the conditions,
limitations and provisions set forth herein.

         1.       EXERCISE OF WARRANT.

                  1.1 CASH EXERCISE. This Warrant may be exercised, in whole or
in part, at any time, or from time to time during the period commencing on the
date hereof and expiring 5:00 p.m. Eastern Time on May _____, 2005 (the
"Expiration Date"), by presentation and surrender of this Warrant to the Company
at its principal office, or at the office of its stock transfer agent, if any,
with the Warrant Exercise Form attached hereto duly executed and accompanied by
payment (either in cash or by certified or official bank check, payable to the
order of the Company) of the Exercise Price for the number of shares specified
in such form and instruments of transfer, if appropriate, duly executed by the
Holder or his or her duly authorized attorney. If this Warrant should be
exercised in part only, the Company shall, upon surrender of this Warrant for
cancellation, execute and deliver a new Warrant evidencing the rights of the
Holder thereof to purchase the balance of the shares purchasable hereunder. Upon
receipt by the Company of this Warrant, together with the Exercise Price, at its
office, or by the stock transfer agent of the Company at its office, in proper
form for exercise, the Holder shall be deemed to be the holder of record of the
shares of Common Stock issuable upon such exercise, notwithstanding that the
stock transfer books of the Company shall then be closed or that certificates
representing such shares of Common Stock shall not then be actually delivered to
the Holder. The Company shall pay any and all documentary stamp or similar issue
or transfer taxes payable in respect of the issue or delivery of shares of
Common Stock on exercise of this Warrant.

                  1.2 CASHLESS EXERCISE. This Warrant may be exchanged, in whole
or in part (a "Warrant Exchange"), at any time, or from time to time, during the
period commencing on the date hereof and ending on the Expiration Date, into the
number of shares of Common Stock determined in accordance with this Section 1.2,
by presentation and surrender of this Warrant to the Company at its principal
office, or at the office of its stock transfer agent, if any, accompanied by a
notice (a "Notice of Exchange") stating that this Warrant is being exchanged and
the number of shares of Common Stock to be exchanged. In connection with any
Warrant Exchange, this Warrant shall represent the right to subscribe for and
acquire the number of shares of Common Stock (rounded to the nearest whole
number) equal to (i) the number of shares specified by the Holder in its Notice
of Exchange (the "Total Number") less the number of shares equal to the quotient
obtained by dividing (A) the product of the Total Number and the then




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applicable Exercise Price by (B) the then fair market value (determined in
accordance with Section 3 below) per share of Common Stock. If this Warrant
should be exchanged in part only, the Company shall, upon surrender of this
Warrant for cancellation, execute and deliver a new Warrant evidencing the
rights of the Holder thereof to purchase the balance of the shares purchasable
hereunder. Upon receipt by the Company of this Warrant, together with a duly
executed Notice of Exchange, at its office, or by the stock transfer agent of
the Company at its office, the Holder shall be deemed to be the holder of record
of the shares of Common Stock issuable upon such exchange, notwithstanding that
the stock transfer books of the Company shall then be closed or that
certificates representing such shares of Common Stock shall not then be actually
delivered to the Holder. The Company shall pay any and all documentary stamp or
similar issue or transfer taxes payable in respect of the issue or delivery of
shares of Common Stock on exchange of this Warrant.

         2. RESERVATION OF SHARES. The Company will at all times reserve for
issuance and delivery upon exercise of this Warrant all shares of Common Stock
or other shares of capital stock of the Company (and Other Securities) from time
to time receivable upon exercise of this Warrant. All such shares (and Other
Securities) shall be duly authorized and, when issued upon such exercise, shall
be validly issued, fully paid and non-assessable and free of all preemptive
rights.

         3. FRACTIONAL SHARES. No fractional shares or scrip representing
fractional shares shall be issued upon the exercise of this Warrant, but the
Company shall pay the Holder an amount equal to the fair market value of such
fractional share of Common Stock in lieu of each fraction of a share otherwise
called for upon any exercise of this Warrant. For purposes of this Warrant, the
fair market value of a share of Common Stock shall be determined as follows:

                  (a) If the Common Stock is listed on a National Securities
Exchange or admitted to unlisted trading privileges on such exchange or listed
for trading on the NASDAQ system, the current market value shall be the last
reported sale price of the Common Stock on such exchange or system on the last
business day prior to the date of exercise of this Warrant or if no such sale is
made on such day, the average of the closing bid and asked prices for such day
on such exchange or system; or

                  (b) If the Common Stock is not so listed or admitted to
unlisted trading privileges, the current market value shall be the mean of the
last reported bid and asked prices reported by the National Quotation Bureau,
Inc. on the last business day prior to the date of the exercise of this Warrant;
or

                  (c) If the Common Stock is not so listed or admitted to
unlisted trading privileges and bid and asked prices are not so reported, the
current market value shall be an amount, not less than book value thereof as at
the end of the most recent fiscal year of the Company ending prior to the date
of the exercise of the Warrant, determined by the Board of Directors of the
Company in good faith.



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         4. EXCHANGE, TRANSFER, ASSIGNMENT OR LOSS OF WARRANT. This Warrant is
exchangeable, without expense, at the option of the Holder, upon presentation
and surrender hereof to the Company or at the office of its stock transfer
agent, if any, for other Warrants of different denominations, entitling the
Holder or Holders thereof to purchase in the aggregate the same number of shares
of Common Stock purchasable hereunder. Upon surrender of this Warrant to the
Company or at the office of its stock transfer agent, if any, with the
Assignment Form annexed hereto duly executed and funds sufficient to pay any
transfer tax, subject to the provisions of Section 7 hereof, the Company shall,
without charge, execute and deliver a new Warrant in the name of the assignee
named in such instrument of assignment and this Warrant shall promptly be
canceled. This Warrant may be divided or combined with other Warrants that carry
the same rights upon presentation hereof at the office of the Company or at the
office of its stock transfer agent, if any, together with a written notice
specifying the names and denominations in which new Warrants are to be issued
and signed by the Holder hereof.

         5. RIGHTS OF THE HOLDER. The Holder shall not, by virtue hereof, be
entitled to any rights of a shareholder in the Company, either at law or in
equity, and the rights of the Holder are limited to those expressed in this
Warrant.

         6. ANTI-DILUTION PROVISIONS.

                  6.1 ADJUSTMENT FOR RECAPITALIZATION. If the Company shall at
any time subdivide its outstanding shares of Common Stock (or Other Securities
at the time receivable upon the exercise of the Warrant) by recapitalization,
reclassification or split-up thereof, or if the Company shall declare a stock
dividend or distribute shares of Common Stock to its shareholders, the number of
shares of Common Stock subject to this Warrant immediately prior to such
subdivision shall be proportionately increased and the Exercise Price shall be
proportionately decreased, and if the Company shall at any time combine the
outstanding shares of Common Stock by recapitalization, reclassification or
combination thereof, the number of shares of Common Stock or Other Securities
subject to this Warrant immediately prior to such combination shall be
proportionately decreased and the Exercise Price shall be proportionately
increased. Any such adjustments pursuant to this Section 6.1 shall be effective
at the close of business on the effective date of such subdivision or
combination or if any adjustment is the result of a stock dividend or
distribution then the effective date for such adjustment based thereon shall be
the record date therefor.

                  6.2 ADJUSTMENT FOR REORGANIZATION, CONSOLIDATION, MERGER, ETC.
In case of any reorganization of the Company (or any other entity, the
securities of which are at the time receivable on the exercise of this Warrant)
after the Base Date or in case after such date the Company (or any such other
entity) shall consolidate with or merge into another entity or convey all or
substantially all of its assets to another entity, then, and in each such case,
the Holder of this Warrant upon the exercise thereof as provided in Section 1 at
any time after the consummation of such reorganization, consolidation, merger or
conveyance, shall be entitled to receive, in lieu of the securities and property
receivable upon the exercise of this Warrant prior to such consummation, the
securities or property to which such Holder would have been entitled



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upon such consummation if such Holder had exercised this Warrant immediately
prior thereto; in each such case, the terms of this Warrant shall be applicable
to the securities or property receivable upon the exercise of this Warrant after
such consummation.

                  6.3 NO DILUTION.

                  (a) From the date of issuance of this Warrant until the later
of (1) the first anniversary of the date of such issuance and (2) the date on
which the Company first consummates a sale of shares of its equity securities
(within the meaning of Section 3(a)(11) of the Securities Exchange Act of 1934,
as amended) or debt securities convertible into equity securities for gross cash
proceeds to the Company of more than $2.0 million (such period through such
later date, the "Reset Period") other than Excluded Shares (as hereinafter
defined), if the Company shall issue or enter into any agreement to issue any
shares of Common Stock other than Excluded Shares for consideration per share
(the "Issuance Price") less than the Exercise Price per share in effect
immediately prior to such issuance, the Exercise Price in effect immediately
prior to such issuance shall be reduced (but shall not be increased) to the
Issuance Price. For purposes hereof, the term "Excluded Shares" shall mean (1)
any shares of Common Stock issued in a transaction described in Sections 6.1 and
6.2 of this Warrant; (2) issuances of shares of Common Stock from time to time
pursuant to employment agreements, stock option or bonus plans authorized by the
Board of Directors of the Corporation as of the date hereof, (3) issuances of
Common Stock, or options to acquire shares of Common Stock, or securities
convertible into or exchangeable for Common Stock pursuant to the terms of any
acquisition by the Company of all or substantially all of the operating assets,
or more than fifty percent (50%) of the voting capital stock or other
controlling interest of any business entity in a transaction negotiated on an
arms-length basis and expressly approved in advance by the Board of Directors of
the Company; (4) issuances of shares of Common Stock from time to time upon the
exercise, exchange or conversion of warrants, options, convertible securities,
the Company's outstanding 8 1/4% Subordinated Convertible Notes Due 2003 or
other securities outstanding as of the date hereof and pursuant to the written
terms of such securities as they exist as of the date hereof, and (5) issuances
of shares of Common Stock from time to time pursuant to the anti-dilution
provisions of other securities of the Company, including shares of the Company's
outstanding Series B, Series C and Series D Convertible Preferred Stock. For
purposes hereof, "voting capital stock" shall be deemed to be capital stock of
any class or classes, however designated having ordinary voting power for the
election of members of the board of directors or other governing body and
"controlling" shall mean the possession, directly or indirectly, of the power to
direct or cause the direction of the management and policies of a party, whether
through the ownership of voting capital stock, by contract or otherwise.

                  (b) If, at any time subsequent to the Reset Period and prior
to the first anniversary of the expiration of the Reset Period, the Company
consummates a sale of shares of its Common Stock other than Excluded Shares for
consideration per share of Common Stock less than the Exercise Price per share
in effect immediately prior to such issuance, the Conversion Price in effect
immediately prior to such issuance shall be reduced (but shall not be increased)
to the price (calculated to the nearest cent) determined: by dividing (1) an
amount equal to the sum



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of (A) the number of shares of Common Stock outstanding on a fully diluted basis
immediately prior to such issuance multiplied by the Exercise Price per share in
effect immediately prior to such issuance and (B) the consideration, if any,
received by the Corporation upon such issuance by (2) the number of shares of
Common Stock outstanding on a fully diluted basis immediately after such
issuance.

                  (c) If, at any time from the date of issuance of this Warrant
prior to the first anniversary of the expiration of the Reset Period, the
Company shall issue or enter into any agreement to issue any shares of Common
Stock other than Excluded Shares for consideration per share greater than the
Exercise Price but lower than the market price per share in effect immediately
prior to such issuance, the Exercise Price in effect immediately prior to such
issuance shall be reduced (but shall not be increased) to the price (calculated
to the nearest cent) determined by multiplying the Exercise Price in effect
immediately prior to such issuance by the factor determined by dividing (1) an
amount equal to the sum of (A) the number of shares of Common Stock outstanding
on a fully diluted basis immediately prior to such issuance multiplied by the
market price per share in effect immediately prior to such issuance and (B) the
consideration, if any, received by the Company upon such issuance by (2) the
number of shares of Common Stock outstanding on a fully diluted basis
immediately after such issuance multiplied by the market price per share in
effect immediately prior to such issuance; PROVIDED, however, no adjustment
shall be made to the Exercise Price if (1) such issuance is in connection with a
firm commitment underwritten public offering or (2) the consideration per share
is equal to or greater than 85% of the market price per share in effect
immediately prior to such issuance. For purposes hereof, the "market price" as
of any measurement date shall be the average of the closing prices of the Common
Stock for each of the 10 consecutive trading days immediately preceding such
measurement date.

                  (d) The Company will not, by amendment of its Articles of
Incorporation or through reorganization, consolidation, merger, dissolution,
issue or sale of securities, sale of assets or any other voluntary action, avoid
or seek to avoid the observance or performance of any of the terms of this
Warrant, but will at all times in good faith assist in the carrying out of all
such terms and in the taking of all such action as may be necessary or
appropriate in order to protect the rights of the Holder of this Warrant against
dilution or other impairment.

                  (e) For further clarity, any change to the conversion price or
other terms of the 8 1/4% Subordinated Convertible Notes Due 2003 shall not
count toward determining the Reset Period, but shall be taken into account in
determining whether any adjustment to the Exercise Price is due under this
Section 6.3.

                  (f) The Exercise Price shall be subject to adjustment from
time to time as previously provided in this section 6.3. Upon each adjustment of
the Exercise Price, the holder of the Warrant evidenced hereby shall thereafter
be entitled to purchase, at the Exercise Price resulting from such adjustment,
the number of shares of Common Stock (calculated to the nearest whole share
pursuant to Section 3) obtained by multiplying the Exercise Price in effect





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immediately prior to such adjustment by the number of shares purchasable
pursuant hereto immediately prior to such adjustment and dividing the product by
the Exercise Price resulting from such adjustment.

                  6.4 CERTIFICATE AS TO ADJUSTMENTS. In each case of an
adjustment in the number of shares of Warrant Stock or Other Securities
receivable on the exercise of this Warrant, or the Exercise Price, the Company
at its expense will promptly compute such adjustment in accordance with the
terms of this Warrant and prepare a certificate executed by an executive officer
of the Company setting forth such adjustment and showing in detail the facts
upon which such adjustment is based. The Company will forthwith mail a copy of
each such certificate to the Holder.

                  6.5 NOTICES OF RECORD DATE, ETC. In case:

                  (a) the Company shall take a record of the holders of its
Common Stock (or Other Securities at the time receivable upon the exercise of
the Warrant) for the purpose of entitling them to receive any dividend (other
than a cash dividend at the same rate as the rate of the last cash dividend
theretofore paid) or other distribution, or any right to subscribe for, purchase
or otherwise acquire any shares of stock of any class or any other securities,
or to receive any other right; or

                  (b) of any capital reorganization of the Company, any
reclassification of the capital stock of the Company, any consolidation or
merger of the Company with or into another entity, or any conveyance of all or
substantially all of the assets of the Company to another entity; or

                  (c) of any voluntary or involuntary dissolution, liquidation,
partial liquidation or winding up of the Company, or

                  (d) any event resulting in the expiration of the Reset Period,

then, and in each such case, the Company shall mail or cause to be mailed to
each Holder of the Warrant at the time outstanding a notice specifying, as the
case may be, (i) the date on which a record is to be taken for the purpose of
such dividend, distribution or right, and stating the amount and character of
such dividend, distribution or right, or (ii) the date on which such
reorganization, reclassification, consolidation, merger, conveyance,
dissolution, liquidation or winding up is to take place, and the time, if any,
to be fixed, as to which the holders of record of Common Stock (or such other
securities at the time receivable upon the exercise of the Warrant) shall be
entitled to exchange their shares of Common Stock (or such other securities) for
securities or other property deliverable upon such reorganization,
reclassification, consolidation, merger, conveyance, dissolution, liquidation or
winding up. Such notice shall be mailed at least 20 days prior to the date
therein specified.



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         7. TRANSFER TO COMPLY WITH THE SECURITIES ACT. Notwithstanding any
other provision contained herein, this Warrant and any Warrant Stock or Other
Securities may not be sold, transferred, pledged, hypothecated or otherwise
disposed of except as follows: (a) to a person who, in the opinion of counsel to
the Company, is a person to whom this Warrant or the Warrant Stock or Other
Securities may legally be transferred without registration and without the
delivery of a current prospectus under the Securities Act with respect thereto;
or (b) to any person upon delivery of a prospectus then meeting the requirements
of the Securities Act relating to such securities and the offering thereof for
such sale or disposition, and thereafter to all successive assignees.

         8. LEGEND. Unless the shares of Warrant Stock or Other Securities have
been registered under the Securities Act, upon exercise of any of the Warrants
and the issuance of any of the shares of Warrant Stock or Other Securities, all
certificates representing such securities shall bear on the face thereof
substantially the following legend:

                  The securities represented by this certificate have not been
                  registered under the Securities Act of 1933, as amended, and
                  may not be sold, offered for sale, assigned, transferred or
                  otherwise disposed of, unless registered pursuant to the
                  provisions of that Act or unless an opinion of counsel is
                  obtained stating that such disposition is in compliance with
                  an available exemption from such registration.

         9. NOTICES. All notices required hereunder shall be in writing and
shall be deemed given when telegraphed, delivered personally or within two days
after mailing when mailed by certified or registered mail, return receipt
requested, to the Company at its principal office, or to the Holder at the
address set forth on the record books of the Company, or at such other address
of which the Company or the Holder has been advised by notice hereunder.

         10. APPLICABLE LAW. The Warrant is issued under and shall for all
purposes be governed by and construed in accordance with the laws of the State
of Florida, without giving effect to the choice of law rules thereof.




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         IN WITNESS HEREOF, the Company has caused this Warrant to be signed on
its behalf, in its corporate name, by its duly authorized officer, all as of the
day and year first above written.


                                          MANSUR INDUSTRIES INC.


                                          By:
                                             --------------------------------
                                          Name:  Paul Mansur
                                          Title: Chief Executive Officer








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                              WARRANT EXERCISE FORM

The undersigned hereby irrevocably elects to exercise the within Warrant to the
extent of purchasing ____________ shares of Common Stock of Mansur Industries
Inc., a Florida corporation, and hereby makes payment of $____________ in
payment therefor.



                                     ---------------------------------------
                                     Signature



                                     ---------------------------------------
                                     Signature, if jointly held



                                     ---------------------------------------
                                     Date





                       INSTRUCTIONS FOR ISSUANCE OF STOCK
         (if other than to the registered holder of the within Warrant)



Name
    ----------------------------------------------------------------------------
                      (Please typewrite or print in block letters)

Address
       -------------------------------------------------------------------------

--------------------------------------------------------------------------------



Social Security or
Taxpayer Identification Number
                              --------------------------------------------------




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                                 ASSIGNMENT FORM



FOR VALUE RECEIVED,
                   ------------------------------------------------------------

hereby sells, assigns and transfers unto

Name
    ----------------------------------------------------------------------------
                  (Please typewrite or print in block letters)

the right to purchase Common Stock of Mansur Industries Inc., a Florida
corporation, represented by this Warrant to the extent of shares as to which
such right is exercisable and does hereby irrevocably constitute and appoint
___________________________________________ Attorney, to transfer the same on
the books of the Company with full power of substitution in the premises.


DATED:  ____________, 200_.





                                     ---------------------------------------
                                     Signature



                                     ---------------------------------------
                                     Signature, if jointly held









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