<PAGE>

                                                                     EXHIBIT 4.3

THE REGISTERED HOLDER OF THIS PURCHASE OPTION BY ITS ACCEPTANCE HEREOF, AGREES
THAT IT WILL NOT SELL, TRANSFER OR ASSIGN THIS PURCHASE OPTION EXCEPT AS HEREIN
PROVIDED.

VOID AFTER 5:00 P.M. EASTERN TIME, _____ _____, 2009.


                                     FORM OF
                                 PURCHASE OPTION

                            FOR THE PURCHASE OF UP TO

                         120,000 SHARES OF COMMON STOCK

                                     AND/OR

                     120,000 COMMON STOCK PURCHASE WARRANTS

                                       OF

                              GIGABEAM CORPORATION

                            (A DELAWARE CORPORATION)


1.       Purchase Option.

         THIS CERTIFIES THAT, in consideration of $100.00 duly paid by or on
behalf of ____________________________ ("Holder"), as registered owner of this
Purchase Option, to GigaBeam Corporation ("Company"), Holder is entitled, at any
time or from time to time at or after _____ ____, 2005 ("Commencement Date"),
and at or before 5:00 p.m., Eastern Time, _____ ____, 2009 ("Expiration Date"),
but not thereafter, to subscribe for, purchase and receive, in whole or in part,
up to One Hundred and Twenty Thousand (120,000) shares of Common Stock of the
Company, $.001 par value ("Common Stock") and/or One Hundred and Twenty Thousand
(120,000) Redeemable Common Stock Purchase Warrants, each to purchase one share
of Common Stock ("Warrants"). Each Warrant is the same as the Redeemable Common
Stock Purchase Warrants ("Public Warrants") that have been registered by the
Company for sale to the public pursuant to the Registration Statement on Form
SB-2 (No.333-116020) ("Registration Statement"), which was declared effective on
______, 2004 ("Effective Date"). The shares of Common Stock and Warrants are
sometimes collectively referred to herein as the "Securities." The Holder can
purchase, upon exercise of the Purchase Option, either shares of Common Stock or
Warrants or both. If the Expiration Date is a day on which banking institutions
are authorized by law to close, then this Purchase Option may be exercised on
the next succeeding day that is not such a day in accordance with the terms
herein. This Purchase Option is initially exercisable at $5.555 per share of
Common Stock and $0.055 per Warrant purchased; provided, however, that upon the
occurrence of any of the events specified in Section 6 hereof, the rights
granted by this Purchase Option, including the exercise price and the number of
shares of Common Stock and Warrants to be received upon such exercise, shall be
adjusted as therein specified. The term "Exercise Price" shall mean the initial
exercise price or the adjusted exercise price, depending on the context of a
share of Common Stock or a Warrant.


<PAGE>

2.       Exercise.

         2.1 Exercise Form. In order to exercise this Purchase Option, the
exercise form attached hereto must be duly executed and completed and delivered
to the Company, together with this Purchase Option and payment of the Exercise
Price in cash or by certified check or official bank check for the Securities
being purchased. If the subscription rights represented hereby shall not be
exercised at or before 5:00 p.m., Eastern time, on the Expiration Date, this
Purchase Option shall become and be void without further force or effect, and
all rights represented hereby shall cease and expire.

         2.2 Legend. Each certificate for Securities purchased under this
Purchase Option shall bear a legend as follows (or a substantially similar
legend) unless such Securities have been registered under the Securities Act of
1933, as amended:

             "The securities represented by this certificate have not been
             registered under the Securities Act of 1933, as amended ("Act") or
             applicable state law. The securities may not be offered for sale,
             sold or otherwise transferred except pursuant to an effective
             registration statement under the Act, or pursuant to an exemption
             from registration under the Act and applicable state law."

         2.3 Conversion Right.

         2.3.1 Determination of Amount. In lieu of the payment of the Exercise
Price in the manner required by Section 2.1, the Holder shall have the right
(but not the obligation) to convert any exercisable but unexercised portion of
this Purchase Option into Common Stock and/or Warrants ("Conversion Right") as
provided in this Section 2 below. Notwithstanding anything to the contrary
contained in this Agreement, this Conversion Right shall only be exercisable
with respect to the Warrants after the first anniversary hereof and only if a
registration statement under the Act respecting the Warrants (and the Common
Stock underlying the Warrants)is not then effective.

         2.3.2 Common Stock. Upon exercise of the Conversion Right, the Company
shall deliver to the Holder (without payment by the Holder of any of the
Exercise Price in cash) that number of shares of Common Stock equal to the
quotient obtained by dividing (x) the "Stock Value" (as defined below), at the
close of trading on the next to last trading day immediately preceding the
exercise of the Conversion Right, of the portion of the Purchase Option being
converted by (y) the Market Price at that same time. The "Stock Value" of the
portion of the Purchase Option being converted shall equal the remainder derived
from subtracting (a) the Exercise Price multiplied by the number of shares of
Common Stock underlying that portion of the Purchase Option being converted from
(b) the Market Price of the Common Stock multiplied by the number of shares of
Common Stock underlying that portion of the Purchase Option being converted. As
used in this Section 2.3.2, the term "Market Price" at any date shall be deemed
to be the average of the last reported sale price of the Common Stock for the
three consecutive trading days ending on such date, as officially reported by
the principal securities exchange on which the Common Stock is listed or
admitted to trading, or, if the Common Stock is not listed or admitted to
trading on any national securities exchange or if any such exchange on which the
Common Stock is listed is not its principal trading market, the last reported
sale price for the three consecutive trading days ending on such date as
furnished by the NASD through the Nasdaq National Market or SmallCap Market, or,
if applicable, the OTC Bulletin Board, or if the Common Stock is not listed or
admitted to trading on any of the foregoing markets, or similar organization, as
determined in good faith by resolution of the Board of Directors of the Company,
based on the best information available to it.



                                       2
<PAGE>

         2.3.3 Warrants. Upon exercise of the Conversion Right the Company shall
deliver to the Holder (without payment by the Holder of any of the Exercise
Price in cash) that number of Warrants equal to the quotient obtained by
dividing (x) the "Warrant Value" (as defined below), at the close of trading on
the next to last trading day immediately preceding the exercise of the
Conversion Right, of the portion of the Purchase Option being converted by (y)
the Market Price at that same time. The "Warrant Value" of the portion of the
Purchase Option being converted shall equal the remainder derived from
subtracting (a) the Exercise Price multiplied by the number of Warrants
underlying that portion of the Purchase Option being converted from (b) the
Market Price of the Warrants multiplied by the number of Warrants underlying
that portion of the Purchase Option being converted. As used in this Section
2.3.3, the term "Market Price" at any date shall be deemed to be the last
reported sale price of the Warrants for the three consecutive trading days
ending on such date, or, in case no such reported sale takes place on such day,
the last reported sale price for the immediately preceding trading day, in
either case as officially reported by the principal securities exchange on which
the Warrants are listed or admitted to trading, or, if the Warrants are not
listed or admitted to trading on any national securities exchange or if any such
exchange on which the Warrants are listed is not its principal trading market,
the last reported sale price for the three consecutive trading days ending as
furnished by the NASD through the Nasdaq National Market or SmallCap Market, or,
if applicable, the OTC Bulletin Board, or if the Warrants are not then traded on
any of the foregoing markets, or similar organization, then the "Market Price"
shall equal the remainder derived from subtracting (a) the exercise price of the
underlying Warrant from (b) the "Market Price" of the Common Stock as determined
in Section 2.3.2.

         2.3.4 Mechanics of Conversion. The Conversion Right may be exercised by
the Holder on any business day on or after the Commencement Date and not later
than the Expiration Date by delivering the Purchase Option with a duly executed
exercise form attached hereto with the conversion right section completed to the
Company, exercising the Conversion Right and specifying the total number of
shares of Common Stock and/or Warrants that the Holder will purchase pursuant to
such Conversion Right.

3.       Transfer.

         3.1 General Restrictions. The registered Holder of this Purchase
Option, by its acceptance hereof, agrees that it will not sell, transfer or
assign or hypothecate this Purchase Option prior to the Commencement Date to
anyone other than (i) an officer or partner of such Holder, (ii) an officer of
HCFP/Brenner Securities LLC ("Underwriter") or an officer or partner of any
Selected Dealer or member of the underwriting syndicate in connection with the
Company's public offering with respect to which this Purchase Option has been
issued, or (iii) any Selected Dealer or member of the underwriting syndicate. On
and after the Commencement Date, transfers to others may be made subject to
compliance with or exemptions from applicable securities laws. In order to make
any permitted assignment, the Holder must deliver to the Company the assignment
form attached hereto duly executed and completed, together with the Purchase
Option and payment of all transfer taxes, if any, payable in connection
therewith. The Company shall immediately transfer this Purchase Option on the
books of the Company and shall execute and deliver a new Purchase Option or
Purchase Options of like tenor to the appropriate assignee(s) expressly
evidencing the right to purchase the aggregate number of shares of Common Stock
and Warrants purchasable hereunder or such portion of such number as shall be
contemplated by any such assignment.

         3.2 Restrictions Imposed by the Act. This Purchase Option and the
Securities underlying this Purchase Option shall not be transferred unless and
until (i) the Company has received the opinion of counsel for the Holder that
this Purchase Option or the Securities, as the case may be, may be transferred
pursuant to an exemption from registration under the Act and applicable state
law, the availability of which is established to the reasonable satisfaction of
the Company (the Company hereby agreeing that an opinion of Graubard Miller in
form and substance reasonably satisfactory to the Company or its counsel shall
be deemed satisfactory evidence of the availability of an exemption), or (ii) a
registration statement relating to such Purchase Option or Securities, as the
case may be, has been filed by the Company and declared effective by the
Securities and Exchange Commission and compliance with applicable state law.



                                       3
<PAGE>

4.       New Purchase Options to be Issued.

         4.1 Partial Exercise or Transfer. Subject to the restrictions in
Section 3 hereof, this Purchase Option may be exercised or assigned in whole or
in part. In the event of the exercise or assignment hereof in part only, upon
surrender of this Purchase Option for cancellation, together with the duly
executed exercise or assignment form and funds sufficient to pay any Exercise
Price and/or transfer tax, the Company shall cause to be delivered to the Holder
without charge a new Purchase Option of like tenor to this Purchase Option in
the name of the Holder evidencing the right of the Holder to purchase the
aggregate number of shares of Common Stock and Warrants purchasable hereunder as
to which this Purchase Option has not been exercised or assigned.

         4.2 Lost Certificate. Upon receipt by the Company of evidence
satisfactory to it of the loss, theft, destruction or mutilation of this
Purchase Option and of reasonably satisfactory indemnification, the Company
shall execute and deliver a new Purchase Option of like tenor and date. Any such
new Purchase Option executed and delivered as a result of such loss, theft,
mutilation or destruction shall constitute a substitute contractual obligation
on the part of the Company.

5.       Registration Rights.

         5.1 Demand Registration.

             5.1.1 Grant of Right. The Company, upon written demand ("Initial
Demand Notice") of the Holder(s) of at least 51% of the Purchase Options and/or
the underlying shares of Common Stock and Warrants ("Majority Holders"), agrees
to register on one occasion, all of the Securities underlying such Purchase
Options, including the Common Stock, the Warrants and the Common Stock
underlying the Warrants (collectively the "Registrable Securities"). On such
occasion, the Company will file a registration statement covering the
Registrable Securities within sixty (60) days after receipt of the Initial
Demand Notice and use its reasonable best efforts to have the registration
statement declared effective promptly thereafter. If the Company fails to comply
with the provisions of this Section 5.1.1, the Company shall, in addition to any
other equitable or other relief available to the Holder(s), be liable for any
and all incidental, special and consequential damages sustained by the
Holder(s). The demand for registration may be made at any time during a period
of four years beginning one year from the Effective Date; provided that the
Registrable Securities are not already covered by an effective registration
statement. The Company covenants and agrees to give written notice of its
receipt of any Initial Demand Notice by any Holder(s) to all other registered
Holders of the Purchase Options and/or the Registrable Securities within ten
days from the date of the receipt of any such Initial Demand Notice.



                                       4
<PAGE>

             5.1.2 Terms. The Company shall bear all fees and expenses attendant
to registering the Registrable Securities, but the Holders shall pay any and all
underwriting and brokerage commissions discounts and fees, the expenses of any
legal counsel selected by the Holders to represent them in connection with the
sale of the Registrable Securities. The Company agrees to use its reasonable
best efforts to cause the filing required herein to become effective promptly
and to qualify or register the Registrable Securities in such States as are
reasonably requested by the Holder(s); provided, however, that in no event shall
the Company be required to register the Registrable Securities in a State in
which such registration would cause (i) the Company to be obligated to register
or license to do business in such State or submit to general service of process
in such State, or (ii) the principal stockholders of the Company to be obligated
to escrow their shares of capital stock of the Company. The Company shall cause
any registration statement filed pursuant to the demand right granted under
Section 5.1.1 to remain effective for a period of at least twelve consecutive
months from the date that the Holders of the Registrable Securities covered by
such registration statement are first given the opportunity to sell all of such
securities.

         5.2 "Piggy-Back" Registration.

             5.2.1 Grant of Right. In addition to the demand right of
registration, the Holders of the Purchase Options shall have the right for a
period of six (6) years commencing one year from the Effective Date, to include
the Registrable Securities as part of any other registration of securities filed
by the Company (other than in connection with a transaction contemplated by Rule
145(a) promulgated under the Act or pursuant to Form S-8 or any equivalent
form); provided, however, that if, in the determination of the Company's
managing underwriter or underwriters, if any, for such offering, the inclusion
of the Registrable Securities, when added to the securities being registered by
the Company or the selling stockholder(s), will exceed the maximum amount of the
Company's securities which can be marketed (i) at a price reasonably related to
their then current market value, or (ii) without adversely affecting the entire
offering, the Company shall not be obligated to register such Registrable
Securities.

             5.2.2 Terms. The Company shall bear all fees and expenses attendant
to registering the Registrable Securities, but the Holders shall pay any and all
underwriting and brokerage commissions, discounts and fees and the expenses of
any legal counsel and other experts selected by the Holders to represent them in
connection with the sale of the Registrable Securities. In the event of such a
proposed registration, the Company shall furnish the then Holders of outstanding
Registrable Securities with not less than ten (10) days written notice prior to
the proposed date of filing of such registration statement. Such notice to the
Holders shall continue to be given for each registration statement filed by the
Company until such time as the Holder has sold all of the Registrable
Securities. The holders of the Registrable Securities shall exercise the
"piggy-back" rights provided for herein by giving written notice, within ten
(10) days of the receipt of the Company's notice of its intention to file a
registration statement.



                                       5
<PAGE>

         5.3 General Terms.

             5.3.1 Indemnification. The Company shall indemnify the Holder(s) of
the Registrable Securities to be sold pursuant to any registration statement
hereunder and each person, if any, who controls such Holders within the meaning
of Section 15 of the Act or Section 20(a) of the Securities Exchange Act of
1934, as amended ("Exchange Act"), against all loss, claim, damage, expense or
liability (including all reasonable attorneys' fees and other expenses
reasonably incurred in investigating, preparing or defending against any claim
whatsoever) to which any of them may become subject under the Act, the Exchange
Act or otherwise, arising from such registration statement but only to the same
extent and with the same effect as the provisions pursuant to which the Company
has agreed to indemnify the Underwriter contained in Section 5 of the
Underwriting Agreement between the Underwriter and the Company, dated the
Effective Date (but not with respect to information furnished (or not furnished
in the case of an omission) by the Holders). The Holder(s) of the Registrable
Securities to be sold pursuant to such registration statement, and their
successors and assigns, shall severally, and not jointly, indemnify the Company,
against all loss, claim, damage, expense or liability (including all reasonable
attorneys' fees and other expenses reasonably incurred in investigating,
preparing or defending against any claim whatsoever) to which they may become
subject under the Act, the Exchange Act or otherwise, arising from information
furnished (or not furnished in the case of an omission or alleged omission) by
or on behalf of such Holders, or their successors or assigns, in writing, for
specific inclusion in such registration statement to the same extent and with
the same effect as the provisions contained in Section 5 of the Underwriting
Agreement pursuant to which the Underwriter has agreed to indemnify the Company.


             5.3.2 Exercise of Warrants. Nothing contained in this Purchase
Option shall be construed as requiring the Holder(s) to exercise their Purchase
Options or Warrants prior to or after the initial filing of any registration
statement or the effectiveness thereof.

             5.3.3 Documents Delivered to Holders. Subject to the execution of
appropriate confidentiality agreements, the Company shall deliver promptly to
each Holder participating in the offering requesting the correspondence and
memoranda described below and to the managing underwriter copies of all
correspondence between the Commission and the Company, its counsel or auditors
and all memoranda relating to discussions with the Commission or its staff with
respect to the registration statement and permit each Holder and underwriter to
do such investigation, upon reasonable advance notice, with respect to
information contained in or omitted from the registration statement as it deems
reasonably necessary to comply with applicable securities laws or rules of the
National Association of Securities Dealers, Inc. ("NASD"). Such investigation
shall include access to books, records and properties and opportunities to
discuss the business of the Company with its officers and independent auditors,
all to such reasonable extent and at such reasonable times as any such Holder
shall reasonably request, provided that all such persons sign a confidentiality
agreement.




                                       6
<PAGE>

             5.3.4 Documents to be Delivered by Holder(s). Each of the Holder(s)
participating in any of the foregoing offerings shall furnish to the Company a
completed and executed questionnaire provided by the Company requesting
information customarily sought of selling securityholders as a condition to the
inclusion of such Holder's Registrable Securities in any registration statement.


6. Adjustments.

         6.1 Adjustments to Exercise Price and Number of Securities. The
Exercise Price and the number of shares of Common Stock underlying the Purchase
Option and underlying the Warrants underlying the Purchase Option shall be
subject to adjustment from time to time as hereinafter set forth:

             6.1.1 Stock Dividends - Recapitalization, Reclassification,
Split-Ups. If after the date hereof, and subject to the provisions of Section
6.3 below, the number of outstanding shares of Common Stock is increased by a
stock dividend payable in shares of Common Stock or by a split-up,
recapitalization or reclassification of shares of Common Stock or other similar
event, then, on the effective date thereof, the number of shares of Common Stock
issuable on exercise of the Purchase Option and the Warrants underlying the
Purchase Option shall be increased in proportion to such increase in outstanding
shares; provided, however, that nothing in this Section 6.1 is intended to
provide for an adjustment with respect to the Warrants beyond that provided for
in the Warrant Agreement between the Company and Continental Stock Transfer &
Trust Company. For example, if the Company declares a two-for-one stock dividend
and at the time of such dividend the Purchase Option is for the purchase of
1,000 shares of Common Stock at $5.555 per share and 1,000 Warrants at $0.055
per Warrant (each Warrant exercisable for $5.05 per share), upon effectiveness
of the dividend, the Purchase Option will be adjusted (disregarding for purposes
of this example that adjustments shall be rounded to the nearest cent, as
provided in Section 6.1.3) to allow for the purchase of 2,000 shares at $2.7775
per share and 2,000 Warrants at $0.0275 (each Warrant exercisable for $2.525 per
share).

             6.1.2 Aggregation of Shares. If after the date hereof, and subject
to the provisions of Section 6.3, the number of outstanding shares of Common
Stock is decreased by a consolidation, combination or reclassification of shares
of Common Stock or other similar event, then, upon the effective date thereof,
the number of shares of Common Stock issuable on exercise of the Purchase Option
and the Warrants underlying the Purchase Option shall be decreased in proportion
to such decrease in outstanding shares.




                                       7
<PAGE>

             6.1.3 Adjustments in Exercise Price. Whenever the number of shares
of Common Stock purchasable upon the exercise of this Purchase Option is
adjusted, as provided in this Section 6.1, the Exercise Price shall be adjusted
(to the nearest cent) by multiplying such Exercise Price immediately prior to
such adjustment by a fraction (x) the numerator of which shall be the number of
shares of Common Stock purchasable upon the exercise of this Purchase Option
immediately prior to such adjustment, and (y) the denominator of which shall be
the number of shares of Common Stock so purchasable immediately thereafter. If
it is determined that such Exercise Price and number of shares of Common Stock
must be adjusted, then the Exercise Price of the Purchase Option with respect to
the underlying Warrants and the number of Warrants purchasable hereunder shall
also be similarly adjusted.

             6.1.4 Replacement of Securities upon Reorganization, etc. In case
of any reclassification or reorganization of the outstanding shares of Common
Stock other than a change covered by Section 6.1.1 hereof or which solely
affects the par value of such shares of Common Stock, or in the case of any
merger or consolidation of the Company with or into another corporation (other
than a consolidation or merger in which the Company is the continuing
corporation and which does not result in any reclassification or reorganization
of the outstanding shares of Common Stock), or in the case of any sale or
conveyance to another corporation or entity of the property of the Company as an
entirety or substantially as an entirety in connection with which the Company is
dissolved, the Holder of this Purchase Option shall have the right thereafter
(until the expiration of the right of exercise of this Purchase Option) to
receive upon the exercise hereof, for the same aggregate Exercise Price payable
hereunder immediately prior to such event, the kind and amount of shares of
stock or other securities or property (including cash) receivable upon such
reclassification, reorganization, merger or consolidation, or upon a dissolution
following any such sale or other transfer, by a Holder of the number of shares
of Common Stock of the Company obtainable upon exercise of this Purchase Option
immediately prior to such event; and if any reclassification also results in a
change in shares of Common Stock covered by Section 6.1.1, then such adjustment
shall be made pursuant to Sections 6.1.1, 6.1.3 and this Section 6.1.4. The
provisions of this Section 6.1.4 shall similarly apply to successive
reclassifications, reorganizations, mergers or consolidations, sales or other
transfers.

             6.1.5 Changes in Form of Purchase Option. This form of Purchase
Option need not be changed because of any change pursuant to this Section, and
Purchase Options issued after such change may state the same Exercise Price and
the same number of shares of Common Stock and Warrants as are stated in the
Purchase Options initially issued pursuant to this Agreement. The acceptance by
any Holder of the issuance of new Purchase Options reflecting a required or
permissive change shall not be deemed to waive any rights to a prior adjustment
or the computation thereof.

         6.2 [Intentionally Omitted]

         6.3 Elimination of Fractional Interests. The Company shall not be
required to issue certificates representing fractions of shares of Common Stock
or Warrants upon the exercise or transfer of the Purchase Option, nor shall it
be required to issue scrip or pay cash in lieu of any fractional interests, it
being the intent of the parties that all fractional interests shall be
eliminated by rounding any fraction up or down to the nearest whole number of
Warrants, shares of Common Stock or other securities, properties or rights.



                                       8
<PAGE>

7. Reservation and Listing. The Company shall at all times reserve and keep
available out of its authorized shares of Common Stock, solely for the purpose
of issuance upon exercise of the Purchase Options or the Warrants, such number
of shares of Common Stock or other securities, properties or rights as shall be
issuable upon the exercise thereof. The Company covenants and agrees that, upon
exercise of the Purchase Options and payment of the Exercise Price therefor, all
shares of Common Stock and other securities issuable upon such exercise shall be
duly and validly issued, fully paid and non-assessable and not subject to
preemptive rights of any stockholder. The Company further covenants and agrees
that upon exercise of the Warrants underlying the Purchase Options and payment
of the respective Warrant exercise price therefor, all shares of Common Stock
and other securities issuable upon such exercises shall be duly and validly
issued, fully paid and non-assessable and not subject to preemptive rights of
any stockholder. As long as the Purchase Options shall be outstanding, the
Company shall use its reasonable best efforts to cause all (i) shares of Common
Stock issuable upon exercise of the Purchase Options and the Warrants, and (ii)
the Warrants underlying the Purchase Options to be listed (subject to official
notice of issuance) on all securities exchanges (or, if applicable on Nasdaq) on
which the Common Stock or the Public Warrants issued to the public in connection
herewith are then listed and/or quoted.

8. Certain Notice Requirements.

             8.1 Holder's Right to Receive Notice. Nothing herein shall be
construed as conferring upon the Holders the right to vote or consent or to
receive notice as a stockholder for the election of directors or any other
matter, or as having any rights whatsoever as a stockholder of the Company. If,
however, at any time prior to the expiration of the Purchase Options and their
exercise, any of the events described in Section 8.2 shall occur, then, in one
or more of said events, the Company shall give written notice of such event at
least ten (10) days prior to the date fixed as a record date or the date of
closing the transfer books for the determination of the stockholders entitled to
such dividend, distribution, conversion or exchange of securities or
subscription rights, or entitled to vote on such proposed dissolution,
liquidation, winding up or sale. Such notice shall specify such record date or
the date of the closing of the transfer books, as the case may be.

             8.2 Events Requiring Notice. The Company shall be required to give
the notice described in this Section 8 upon one or more of the following events:
(i) if the Company shall take a record of the holders of its shares of Common
Stock for the purpose of entitling them to receive a dividend or distribution
payable otherwise than in cash, or a cash dividend or distribution payable
otherwise than out of retained earnings, as indicated by the accounting
treatment of such dividend or distribution on the books of the Company, or (ii)
the Company shall offer to all the holders of its Common Stock any additional
shares of capital stock of the Company or securities convertible into or
exchangeable for shares of capital stock of the Company, or any option, right or
warrant to subscribe therefor, or (iii) a dissolution, liquidation or winding up
of the Company (other than in connection with a consolidation or merger) or a
sale of all or substantially all of its property, assets and business shall be
proposed.




                                       9
<PAGE>

         8.3 Notice of Change in Exercise Price. The Company shall, promptly
after an event requiring a change in the Exercise Price pursuant to Section 6
hereof, send notice to the Holders of such event and change ("Price Notice").
The Price Notice shall describe the event causing the change and the method of
calculating same and shall be certified as being true and accurate by the
Company's President and Chief Financial Officer.

         8.4 Transmittal of Notices. All notices, requests, consents and other
communications under this Purchase Option shall be in writing and shall be
deemed to have been duly made on the date of delivery if delivered personally or
sent by overnight courier, with acknowledgement of receipt to the party to which
notice is given, or on the fifth day after mailing if mailed to the party to
whom notice is to be given, by registered or certified mail, return receipt
requested, postage prepaid and properly addressed as follows: (i) if to the
registered Holder of the Purchase Option, to the address of such Holder as shown
on the books of the Company, or (ii) if to the Company, to its principal
executive office.

9. Miscellaneous.

         9.1 Amendments. The Company and the Underwriter may from time to time
supplement or amend this Purchase Option without the approval of any of the
Holders in order to cure any ambiguity, to correct or supplement any provision
contained herein which may be defective or inconsistent with any other
provisions herein, or to make any other provisions in regard to matters or
questions arising hereunder which the Company and the Underwriter may deem
necessary or desirable and which the Company and the Underwriter deem shall not
adversely affect the interest of the Holders. All other modifications or
amendments shall require the written consent of the party against whom
enforcement of the modification or amendment is sought.

         9.2 Headings. The headings contained herein are for the sole purpose of
convenience of reference, and shall not in any way limit or affect the meaning
or interpretation of any of the terms or provisions of this Purchase Option.

         9.3 Entire Agreement. This Purchase Option (together with the other
agreements and documents being delivered pursuant to or in connection with this
Purchase Option) constitutes the entire agreement of the parties hereto with
respect to the subject matter hereof, and supersedes all prior agreements and
understandings of the parties, oral and written, with respect to the subject
matter hereof.




                                       10
<PAGE>

         9.4 Binding Effect. This Purchase Option shall inure solely to the
benefit of and shall be binding upon, the Holder and the Company and their
respective successors, legal representatives and assigns, and no other person
shall have or be construed to have any legal or equitable right, remedy or claim
under or in respect of or by virtue of this Purchase Option or any provisions
herein contained.

         9.5 Governing Law; Submission to Jurisdiction. This Purchase Option
shall be governed by and construed and enforced in accordance with the laws of
the State of New York, without giving effect to conflict of laws. The Company
hereby agrees that any action, proceeding or claim against it arising out of, or
relating in any way to this Purchase Option shall be brought and enforced in the
courts of the State of New York or of the United States of America for the
Southern District of New York, and irrevocably submits to such jurisdiction,
which jurisdiction shall be exclusive. The Company hereby waives any objection
to such exclusive jurisdiction and that such courts represent an inconvenient
forum. Any process or summons to be served upon the Company may be served by
transmitting a copy thereof by registered or certified mail, return receipt
requested, postage prepaid, addressed to it at the address set forth in Section
8 hereof. Such mailing shall be deemed personal service and shall be legal and
binding upon the Company in any action, proceeding or claim. The Company and the
Holder, by acceptance hereof, agree that the prevailing party(ies) in any such
action shall be entitled to recover from the other party(ies) all of its
reasonable attorneys' fees and expenses relating to such action or proceeding
and/or incurred in connection with the preparation therefor.

         9.6 Waiver, Etc. The failure of the Company or the Holder to at any
time enforce any of the provisions of this Purchase Option shall not be deemed
or construed to be a waiver of any such provision, nor to in any way affect the
validity of this Purchase Option or any provision hereof or the right of the
Company or any Holder to thereafter enforce each and every provision of this
Purchase Option. No waiver of any breach, non-compliance or non-fulfillment of
any of the provisions of this Purchase Option shall be effective unless set
forth in a written instrument executed by the party or parties against whom or
which enforcement of such waiver is sought; and no waiver of any such breach,
non-compliance or non-fulfillment shall be construed or deemed to be a waiver of
any other or subsequent breach, non-compliance or non-fulfillment.





                                       11
<PAGE>




         IN WITNESS WHEREOF, the Company has caused this Purchase Option to be
signed by its duly authorized officer as of the ____ day of _____, 2004.


                                           GIGABEAM CORPORATION



                                           By:__________________________________
                                                 Louis S. Slaughter
                                                 Chief Executive Officer





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<PAGE>



Form to be used to exercise Purchase Option:

GigaBeam Corporation


Date:_________________, 200__

         The undersigned hereby elects irrevocably to exercise the within
Purchase Option and to purchase ____ shares of Common Stock and/or Warrants to
purchase ______ shares of Common Stock of GigaBeam Corporation and hereby makes
payment of $____________ (at the rate of $_________ per share of Common Stock
and $____________ per Warrant) in payment of the Exercise Price pursuant
thereto. Please issue the Common Stock and Warrants as to which this Purchase
Option is exercised in accordance with the instructions given below.

                                       or

         The undersigned hereby elects irrevocably to exercise the within
Purchase Option and to purchase _________ shares of Common Stock by surrender of
the unexercised portion of the within Purchase Option (with a "Stock Value" of
$_______ based on a "Market Price" of $__________. Please issue the Common Stock
as to which this Purchase Option is exercised in accordance with the
instructions given below.

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

         NOTICE: THE SIGNATURE TO THIS FORM MUST CORRESPOND WITH THE NAME AS
WRITTEN UPON THE FACE OF THE WITHIN PURCHASE OPTION IN EVERY PARTICULAR WITHOUT
ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATSOEVER.


                   INSTRUCTIONS FOR REGISTRATION OF SECURITIES


Name     ________________________________________________________
                           (Print in Block Letters)

Address  ________________________________________________________




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<PAGE>



Form to be used to assign Purchase Option:


                                   ASSIGNMENT


         (To be executed by the registered Holder to effect a transfer of the
within Purchase Option):

         FOR VALUE RECEIVED,__________________________________ does hereby sell,
assign and transfer unto _______________________ the right to purchase
_______________________ shares of Common Stock and/or Warrants to purchase
______ shares of Common Stock of GigaBeam Corporation ("Company") evidenced by
the within Purchase Option and does hereby authorize the Company to transfer
such right on the books of the Company.

Dated:___________________, 200_


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

------------------------------
Signature Guaranteed

         NOTICE: THE SIGNATURE TO THIS FORM MUST CORRESPOND WITH THE NAME AS
WRITTEN UPON THE FACE OF THE WITHIN PURCHASE OPTION IN EVERY PARTICULAR WITHOUT
ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATSOEVER, AND MUST BE GUARANTEED BY A
BANK, OTHER THAN A SAVINGS BANK, OR BY A TRUST COMPANY OR BY A FIRM HAVING
MEMBERSHIP ON A REGISTERED NATIONAL SECURITIES EXCHANGE.





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