Exhibit 4.5


 


EXHIBIT A


 


Form of Representative’s Warrant Agreement


 


THE REGISTERED HOLDER OF THIS PURCHASE WARRANT
BY ITS ACCEPTANCE HEREOF, AGREES THAT IT WILL NOT SELL, TRANSFER OR ASSIGN THIS PURCHASE WARRANT EXCEPT AS HEREIN PROVIDED AND THE REGISTERED
HOLDER OF THIS PURCHASE WARRANT AGREES THAT IT WILL NOT SELL, TRANSFER, ASSIGN, PLEDGE OR HYPOTHECATE THIS PURCHASE WARRANT FOR A PERIOD
OF ONE HUNDRED EIGHTY DAYS FOLLOWING THE EFFECTIVE DATE (DEFINED BELOW) TO ANYONE OTHER THAN (I) EF HUTTON, DIVISION OF BENCHMARK INVESTMENTS,
LLC OR AN UNDERWRITER OR A SELECTED DEALER IN CONNECTION WITH THE OFFERING, OR (II) A BONA FIDE OFFICER OR PARTNER OF EF HUTTON, DIVISION
OF BENCHMARK INVESTMENTS, LLC OR OF ANY SUCH UNDERWRITER OR SELECTED DEALER.


 


THIS PURCHASE WARRANT IS NOT EXERCISABLE PRIOR
TO _____________, 2023. [DATE THAT IS SIX MONTHS FROM THE DATE OF THE COMMENCEMENT OF SALES OF THIS PUBLIC SECURITIES IN THE INITIAL
PUBLIC OFFERING.]


VOID AFTER 5:00 P.M., EASTERN TIME, ___________,
2027. [DATE THAT IS FIVE YEARS FROM THE EFFECTIVE DATE OF THIS OFFERING]


 


COMMON STOCK PURCHASE WARRANT


 


For the Purchase of [__] Shares of Common Stock


of


CASTELLUM, INC.


 


1. Purchase Warrant. THIS CERTIFIES THAT,
in consideration of funds duly paid by or on behalf of EF Hutton, division of Benchmark Investments, LLC (“Holder”),
as registered owner of this Purchase Warrant, Castellum, Inc., a Nevada corporation (collectively with its subsidiaries and affiliates,
including, without limitation, all entities disclosed or described in the Registration Statement as being subsidiaries (the “Company”),
Holder is entitled, at any time or from time to time from _______, 2023 [DATE THAT IS SIX MONTHS FROM THE DATE OF THE COMMENCEMENT
OF SALES OF THE PUBLIC SECURITIES IN THIS INITIAL PUBLIC OFFERING] (the “Commencement Date”), and at or before
5:00 p.m., Eastern time, _______, 2027 [DATE THAT IS FIVE YEARS FROM THE EFFECTIVE DATE OF THIS OFFERING] (the “Expiration
Date”), but not thereafter, to subscribe for, purchase and receive, in whole or in part, up to [●]1
shares of common stock of the Company (the “Shares”), subject to adjustment as provided in Section
6 hereof. If the Expiration Date is a day on which banking institutions are authorized by law to close, then this Purchase Warrant
may be exercised on the next succeeding day which is not such a day in accordance with the terms herein. During the period ending on
the Expiration Date, the Company agrees not to take any action that would terminate this Purchase Warrant. This Purchase Warrant is initially
exercisable at a price of $___ per Share; provided, however, that upon the occurrence of any of the events specified in
Section 6 hereof, the rights granted by this Purchase Warrant, including the exercise price per Share and the number of Shares
to be received upon such exercise, shall be adjusted as therein specified. The term “Exercise Price” shall mean the
initial exercise price of $____ per Share (equal to 115% of the initial public offering price) or the adjusted exercise price, depending
on the context. The term “Effective Date” shall mean ___________, 2022, the date on which the Registration Statement
on Form S-1 (File No. 333-267249) of the Company (“Registration Statement”) was declared effective by the Securities
and Exchange Commission (the “Commission”). 


 


 






1
3% of the aggregate number of Common Stocks sold in the Offering (including Option Shares).




    	 



     


    

  


2. Exercise.


 


2.1 Exercise Form.
In order to exercise this Purchase Warrant, the exercise form attached hereto must be duly executed and completed and delivered to the
Company, together with this Purchase Warrant and payment of the Exercise Price for the Shares being purchased payable in cash by wire
transfer of immediately available funds to an account designated by the Company or by certified check or official bank check. 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 Warrant shall
become and be void without further force or effect, and all rights represented hereby shall cease and expire.


  


2.2 Cashless Exercise.
If at any time after 90 days after the Commencement Date there is no effective registration statement registering, or no current prospectus
available for, the resale of the Shares by the Holder, and Holder is not engaged by the Company to conduct a then pending registered offering,
then in lieu of exercising this Purchase Warrant by payment of cash or check payable to the order of the Company pursuant to Section
2.1 above, Holder may elect to receive the number of Shares equal to the value of this Purchase Warrant (or the portion thereof being
exercised), by surrender of this Purchase Warrant to the Company, together with the exercise form attached hereto, in which event the
Company shall issue to Holder, Shares in accordance with the following formula:


 


	X	=	Y(A-B)	 
	A	 


 


	Where,	 	 	 
	 	X	=	The number of Shares to be issued to Holder;
	 	Y	=	The number of Shares for which the Purchase Warrant is being exercised;
	 	A	=	The fair market value of one Share; and
	 	B	=	The Exercise Price.


 


For purposes of this Section
2.2, the fair market value of a Share is defined as follows:


 


	 	(i)	if the Company’s common stock is traded on a securities exchange, the value shall be deemed to be the closing price on such exchange on the trading day immediately prior to the exercise form being received by the Company in connection with the exercise of the Purchase Warrant; or
	 	 	 
	 	(ii)	if the Company’s common stock is actively traded over-the-counter, the value shall be deemed to be the closing bid price on the trading day prior to the exercise form being received by the Company in connection with the exercise of the Purchase Warrant; if there is no active public market, the value shall be the fair market value thereof, as determined in good faith by the Company’s Board of Directors.


 


2.3 Legend. If at any
time after the Commencement Date there is no effective registration statement registering, or no current prospectus available for, the
resale of the Shares by the Holder, each certificate for the securities purchased under this Purchase Warrant shall bear a legend as follows
unless such securities have been registered under the Securities Act of 1933, as amended (the “Securities Act”):


 


“THE SECURITIES REPRESENTED BY
THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), OR APPLICABLE
STATE LAW. NEITHER THE SECURITIES NOR ANY INTEREST THEREIN MAY BE OFFERED FOR SALE, SOLD OR OTHERWISE TRANSFERRED EXCEPT PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT, OR PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT AND
APPLICABLE STATE LAW WHICH, IN THE OPINION OF COUNSEL TO THE COMPANY, IS AVAILABLE.”


 


3. Transfer Restrictions.


 


3.1 General Restrictions.
The registered Holder of this Purchase Warrant agrees by his, her or its acceptance hereof, that such Holder will not: (a) sell, transfer,
assign, pledge or hypothecate this Purchase Warrant for a period of one hundred eighty (180) days following the Commencement Date to anyone
other than: (i) EF Hutton, division of Benchmark Investments, LLC (“EF Hutton”) or an underwriter or a selected dealer
participating in the Offering, or (ii) a bona fide officer or partner of EF Hutton or of any such underwriter or selected dealer, in each
case in accordance with FINRA Rule 5110(e)(1), or (b) for a period of one hundred eighty (180) days following the Commencement Date, cause
this Purchase Warrant or the securities issuable hereunder to be the subject of any hedging, short sale, derivative, put or call transaction
that would result in the effective economic disposition of this Purchase Warrant or the securities hereunder, except as provided for in
FINRA Rule 5110(e)(2). On and after 180 days 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 Warrant and payment of all transfer taxes, if any, payable
in connection therewith. The Company shall within five (5) business days transfer this Purchase Warrant on the books of the Company and
shall execute and deliver a new Purchase Warrant or Purchase Warrants of like tenor to the appropriate assignee(s) expressly evidencing
the right to purchase the aggregate number of Shares purchasable hereunder or such portion of such number as shall be contemplated by
any such assignment.


 




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3.2 Restrictions Imposed
by the Securities Act. If at any time after the Commencement Date there is no effective registration statement registering, or no
current prospectus available for, the resale of the Shares by the Holder, the securities evidenced by this Purchase Warrant shall not
be transferred unless and until: (i) the Company has received the opinion of counsel for the Holder that the securities may be transferred
pursuant to an exemption from registration under the Securities Act and applicable state securities laws, the availability of which is
established to the reasonable satisfaction of the Company (the Company hereby agreeing that the opinion of Carmel, Milazzo & Feil
LLP shall be deemed satisfactory evidence of the availability of an exemption), or (ii) a registration statement or a post-effective amendment
to the Registration Statement relating to the offer and sale of such securities has been filed by the Company and declared effective by
the Commission and compliance with applicable state securities law has been established.


 


4 Registration Rights.


 


4.1 Demand Registration.


 


4.1.1 Grant of Right.
If, after the Commencement Date, there is no effective registration statement registering, or no current prospectus available for, the
resale of the Shares by the Holder, he Company, upon written demand (a “Demand Notice”) of the Holders of at least
51% of the Purchase Warrants and/or the underlying Shares, agrees to register, on one (1) occasion, all or any portion of Shares for which
the Purchase Warrant is exercisable (collectively, the “Registrable Securities”). On such occasion, the Company will
file a registration statement with the Commission covering the Registrable Securities within sixty (60) days after receipt of a Demand
Notice and use its reasonable best efforts to have the registration statement declared effective promptly thereafter, subject to compliance
with review by the Commission; provided, however, that the Company shall not be required to comply with a Demand Notice
if the Company has filed a registration statement with respect to which the Holder is entitled to piggyback registration rights pursuant
to Section 4.2 hereof and either: (i) the Holder has elected to participate in the offering covered by such registration statement
or (ii) if such registration statement relates to an underwritten primary offering of securities of the Company; provided further that
the foregoing proviso shall not apply on or after the date on which the offering covered by such registration statement has been withdrawn
or is thirty (30) days after such offering is consummated. The Company covenants and agrees to give written notice of its receipt of any
Demand Notice by any Holders to all other registered Holders of the Purchase Warrants and/or the Registrable Securities within ten (10)
days after the date of the receipt of any such Demand Notice. Notwithstanding anything to the contrary, the obligations of the Company
pursuant to this Section 4.1 shall not be applicable so long as the Company’s Registration Statement on Form S-1 (File No.
333-[*]) covering the Registrable Securities remains effective.


 




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4.1.2 Terms. The Company
shall bear all fees and expenses attendant to the registration of the Registrable Securities pursuant to Section 4.1.1, but the
Holders shall pay any and all underwriting commissions and 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 filings
required herein to become effective promptly and to qualify or register the Registrable Securities in such states of the Unites States
of America or such foreign jurisdictions as may be reasonably requested by the Holders; provided, however, that in no event
shall the Company be required to register the Registrable Securities in such states or jurisdictions in which such registration would
cause: (i) the Company to be obligated to register or license to do business in such state or jurisdiction or submit to general service
of process therein, 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 4.1.1 to remain effective
for a period of at least twelve (12) consecutive months after 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. The Holders shall only use the prospectuses provided
by the Company to sell the shares covered by such registration statement and will immediately cease to use any prospectus furnished by
the Company if the Company advises the Holder that such prospectus may no longer be used due to a material misstatement or omission. Notwithstanding
the provisions of this Section 4.1.2, the Holder shall be entitled to a demand registration under this Section 4.1.2 on
only one (1) occasion in accordance with FINRA Rule 5110(g)(8)(B) and such demand registration right shall terminate on the fifth anniversary
of the Effective Date in accordance with FINRA Rule 5110(g)(8)(C).


 


4.2 “Piggy-Back”
Registration.


 


4.2.1 Grant of Rights.
In addition to the demand right of registration described in Section 4.1 hereof, the Holder shall have the right, for a period
of five (5) years from the Effective Date in accordance with FINRA Rule 5110(g)(8)(D), 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 Securities Act or pursuant to Form S-8 or Form S-4; equivalent form); provided, however, that if, solely in connection
with any primary underwritten public offering for the account of the Company, the managing underwriter(s) thereof shall, in its reasonable
discretion, impose a limitation on the number of Registrable Securities which may be included in the Registration Statement because, in
such underwriter(s)’ judgment, marketing or other factors dictate such limitation is necessary to facilitate public distribution,
then the Company shall be obligated to include in such Registration Statement only such limited portion of the Registrable Securities
with respect to which the Holder requested inclusion hereunder as the underwriter shall reasonably permit. Any exclusion of Registrable
Securities shall be made pro rata among the Holders seeking to include Registrable Securities in proportion to the number of Registrable
Securities sought to be included by such Holders; provided, however, that the Company shall not exclude any Registrable
Securities unless the Company has first excluded all outstanding securities, the holders of which are not entitled to inclusion of such
securities in such Registration Statement or are not entitled to pro rata inclusion with the Registrable Securities. Notwithstanding anything
to the contrary, the obligations of the Company pursuant to this Section 4.2 shall not be applicable so long as the Company’s
Registration Statement on Form S-1 (File No. 333-[*]) covering the Registrable Securities remains effective.


 


4.2.2 Terms. The Company
shall bear all fees and expenses attendant to registering the Registrable Securities pursuant to Section 4.2.1 hereof, but the
Holders shall pay any and all underwriting commissions and the expenses of any legal counsel 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 thirty (30) 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 all of the Registrable Securities have been sold by the Holder. 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. Except as otherwise provided in this Purchase Warrant, there
shall be no limit on the number of times the Holder may request registration under this Section 4.2; provided, however,
that such registration rights shall terminate on the fifth (5th) anniversary of the Commencement Date.


 


4.3 General Terms.


 


4.3.1 Indemnification.
The Company shall indemnify the Holders 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 Securities 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 Securities 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 Underwriters contained in Section 5.1 of the Underwriting Agreement between the Underwriters (as defined therein) and the Company,
dated ___________, 2022 with respect to the Company’s initial public offering of the Shares. The Holders 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 Securities
Act, the Exchange Act or otherwise, arising from information furnished 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 5.2 of the Underwriting Agreement pursuant to which the Underwriters have agreed to indemnify the Company.


 




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4.3.2 Exercise of Purchase
Warrants. Nothing contained in this Purchase Warrant shall be construed as requiring the Holders to exercise their Purchase Warrants
prior to or after the initial filing of any registration statement or the effectiveness thereof.


 


4.3.3 Documents Delivered
to Holders. The Company shall furnish to each Holder participating in any of the foregoing offerings and to each underwriter of any
such offering, if any, a signed counterpart, addressed to such Holder or underwriter, of: (i) an opinion of counsel to the Company, dated
the effective date of such registration statement (and, if such registration includes an underwritten public offering, an opinion dated
the date of the closing under any underwriting agreement related thereto), and (ii) a “cold comfort” letter dated the effective
date of such registration statement (and, if such registration includes an underwritten public offering, a letter dated the date of the
closing under the underwriting agreement) signed by the independent registered public accounting firm which has issued a report on the
Company’s financial statements included in such registration statement, in each case covering substantially the same matters with
respect to such registration statement (and the prospectus included therein) and, in the case of such accountants’ letter, with
respect to events subsequent to the date of such financial statements, as are customarily covered in opinions of issuer’s counsel
and in accountants’ letters delivered to underwriters in underwritten public offerings of securities. The Company shall also deliver
promptly to each Holder participating in the offering requesting the correspondence and memoranda described below and to the managing
underwriter, if any, copies of all correspondence between the Commission and the Company, its counsel or auditor 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 FINRA. Such investigation shall include access
to books, records and properties and opportunities to discuss the business of the Company with its officers and independent auditor, all
to such reasonable extent and at such reasonable times as any such Holder shall reasonably request.


 


4.3.4 Underwriting Agreement.
The Company shall enter into an underwriting agreement with the managing underwriter(s), if any, selected by any Holders whose Registrable
Securities are being registered pursuant to this Section 4, which managing underwriter shall be reasonably satisfactory to the
Company. Such agreement shall be reasonably satisfactory in form and substance to the Company, each Holder and such managing underwriters,
and shall contain such representations, warranties and covenants by the Company and such other terms as are customarily contained in agreements
of that type used by the managing underwriter. The Holders shall be parties to any underwriting agreement relating to an underwritten
sale of their Registrable Securities and may, at their option, require that any or all the representations, warranties and covenants of
the Company to or for the benefit of such underwriters shall also be made to and for the benefit of such Holders. Such Holders shall not
be required to make any representations or warranties to or agreements with the Company or the underwriters except as they may relate
to such Holders, their Shares, and their intended methods of distribution.


 


4.3.5 Documents to be Delivered
by Holders. Each of the Holders 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 security holders.


 


4.3.6 Damages. Should
the registration or the effectiveness thereof required by Sections 4.1 and 4.2 hereof be delayed by the Company or the Company otherwise
fails to comply with such provisions, the Holders shall, in addition to any other legal or other relief available to the Holders, be entitled
to obtain specific performance or other equitable (including injunctive) relief against the threatened breach of such provisions or the
continuation of any such breach, without the necessity of proving actual damages and without the necessity of posting bond or other security.


 




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4.4 Termination of Registration
Rights. The registration rights afforded to the Holders under this Section 4 shall terminate on the earliest date when all
Registrable Securities of such Holder either: (i) have been publicly sold by such Holder pursuant to a Registration Statement, (ii) have
been covered by an effective Registration Statement on Form S-1 or Form S-3 (or successor form), which may be kept effective as an evergreen
Registration Statement, or (iii) may be sold by the Holder (including on a cashless basis) within a 90-day period without registration
pursuant to Rule 144 or consistent with applicable SEC interpretive guidance (including CD&I No. 201.04 (April 2, 2007) or similar
interpretive guidance).


 


5. New Purchase Warrants to be Issued.


 


5.1 Partial Exercise or
Transfer. Subject to the restrictions in Section 3 hereof, this Purchase Warrant 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 Warrant for cancellation, together
with the duly executed exercise or assignment form and funds sufficient to pay any Exercise Price and/or transfer tax if exercised pursuant
to Section 2.1 hereto, the Company shall cause to be delivered to the Holder without charge a new Purchase Warrant of like tenor
to this Purchase Warrant in the name of the Holder evidencing the right of the Holder to purchase the number of Shares purchasable hereunder
as to which this Purchase Warrant has not been exercised or assigned.


 


5.2 Lost Certificate.
Upon receipt by the Company of evidence satisfactory to it of the loss, theft, destruction or mutilation of this Purchase Warrant and
of reasonably satisfactory indemnification or the posting of a bond, the Company shall execute and deliver a new Purchase Warrant of like
tenor and date. Any such new Purchase Warrant 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.


 


6. Adjustments.


 


6.1 Adjustments to Exercise
Price and Number of Securities. The Exercise Price and the number of Shares underlying the Purchase Warrant shall be subject to adjustment
from time to time as hereinafter set forth:


 


6.1.1 Share Dividends; Split
Ups. If, after the date hereof, and subject to the provisions of Section 6.3 below, the number of outstanding Shares is increased
by a stock dividend payable in Shares or by a split up of Shares or other similar event, then, on the effective day thereof, the number
of Shares purchasable hereunder shall be increased in proportion to such increase in outstanding Shares, and the Exercise Price shall
be proportionately decreased.


 


6.1.2 Aggregation of Shares.
If, after the date hereof, and subject to the provisions of Section 6.3 below, the number of outstanding Shares is decreased by
a consolidation, combination or reclassification of Shares or other similar event, then, on the effective date thereof, the number of
Shares purchasable hereunder shall be decreased in proportion to such decrease in outstanding Shares, and the Exercise Price shall be
proportionately increased.


 


6.1.3 Replacement of Securities
upon Reorganization, etc. In case of any reclassification or reorganization of the outstanding Shares or a variation of share capital
of the Company, other than a change covered by Section 6.1.1 or 6.1.2 hereof or that solely affects the par value of such Shares, or in
the case of any share reconstruction or amalgamation or consolidation of the Company with or into another corporation (other than a consolidation
or share reconstruction or amalgamation in which the Company is the continuing corporation and that does not result in any reclassification
or reorganization of the outstanding Shares), 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
Warrant shall have the right thereafter (until the expiration of the right of exercise of this Purchase Warrant) 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, share reconstruction or amalgamation,
or consolidation, or upon a dissolution following any such sale or transfer, by a Holder of the number of Shares obtainable upon exercise
of this Purchase Warrant immediately prior to such event; and if any reclassification also results in a change in Shares covered by Section
6.1.1 or 6.1.2, then such adjustment shall be made pursuant to Sections 6.1.1, 6.1.2 and this Section 6.1.3. The provisions of this Section
6.1.3 shall similarly apply to successive reclassifications, reorganizations, share reconstructions or amalgamations, or consolidations,
sales or other transfers.


 




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6.1.4 Changes in Form of
Purchase Warrant. This form of Purchase Warrant need not be changed because of any change pursuant to this Section 6.1, and
Purchase Warrants issued after such change may state the same Exercise Price and the same number of Shares as are stated in the Purchase
Warrants initially issued pursuant to this Agreement. The acceptance by any Holder of the issuance of new Purchase Warrants reflecting
a required or permissive change shall not be deemed to waive any rights to an adjustment occurring after the Commencement Date or the
computation thereof.


 


6.2 Substitute Purchase
Warrant. In case of any consolidation of the Company with, or share reconstruction or amalgamation of the Company with or into, another
corporation (other than a consolidation or share reconstruction or amalgamation which does not result in any reclassification or change
of the outstanding Shares), the corporation formed by such consolidation or share reconstruction or amalgamation shall execute and deliver
to the Holder a supplemental Purchase Warrant providing that the holder of each Purchase Warrant then outstanding or to be outstanding
shall have the right thereafter (until the stated expiration of such Purchase Warrant) to receive, upon exercise of such Purchase Warrant,
the kind and amount of shares of stock and other securities and property receivable upon such consolidation or share reconstruction or
amalgamation, by a holder of the number of Shares for which such Purchase Warrant might have been exercised immediately prior to such
consolidation, share reconstruction or amalgamation, sale or transfer. Such supplemental Purchase Warrant shall provide for adjustments
which shall be identical to the adjustments provided for in this Section 6. The above provision of this Section shall similarly
apply to successive consolidations or share reconstructions or amalgamations.


 


6.3 Elimination of Fractional
Interests. The Company shall not be required to issue fractions of Shares upon the exercise of the Purchase Warrant, 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, as the case may be, to the nearest whole number of Shares or other securities,
properties or rights.


 


7. Reservation and Listing. The Company
shall at all times reserve and keep available out of its authorized Shares, solely for the purpose of issuance upon exercise of the Purchase
Warrants, such number of Shares 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 Warrants and payment of the Exercise Price therefor, in accordance with the terms
hereby, all Shares 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. As long as the Purchase Warrants shall be outstanding, the Company shall use its
commercially reasonable efforts to list (subject to official notice of issuance) on all national securities exchanges (or, if applicable,
on the OTC Bulletin Board or any successor trading market) on which the Shares issued to the public in the Offering may then be 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 Warrants 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 fifteen (15) 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. Notwithstanding the foregoing, the Company shall deliver to each Holder a copy of each notice given to the other stockholders
of the Company at the same time and in the same manner that such notice is given to the stockholders.


 




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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 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; (ii) the Company shall offer to all the holders of its Shares
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 share reconstruction or amalgamation) or a sale of all or substantially all of its property,
assets and business shall be proposed.


 


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 Chief Financial
Officer.


 


8.4 Transmittal of Notices.
All notices, requests, consents and other communications under this Purchase Warrant shall be in writing and shall be deemed to have been
duly made when hand delivered or mailed by express mail or private courier service: (i) if to the registered Holder of the Purchase Warrant,
to the address of such Holder as shown on the books of the Company, or (ii) if to the Company, to following address or to such other address
as the Company may designate by notice to the Holders:


 


If to the Holder:


 


EF Hutton, division of Benchmark
Investments, LLC


590 Madison Avenue, 39th Floor


New York, New York 10022


Attn: Mr. Joseph T. Rallo,
Head of Investment Banking


Email:


 


with a copy (which shall not
constitute notice) to:


 


Ross Carmel, Esq.


Carmel, Milazzo & Feil
LLP


55 West 39th Street, 18th
Floor


New York, New York 10018


Email:rc


 


If to the Company:


 


Castellum, Inc.


Attn: Mark C. Fuller, Chief
Executive Officer


3 Bethesda Metro Center Suite
700


Bethesda MD 20814


Email:


  


with a copy (which shall not
constitute notice) to:


 


Joseph M. Lucosky, Esq.


Lucosky Brookman LLP


101 Wood Avenue South, 5th Floor


Woodbridge, NJ 08330


Email:


 




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9. Miscellaneous.


 


9.1 Amendments. The
Company and EF Hutton may from time to time supplement or amend this Purchase Warrant without the approval of any of the Holders in order
to cure any ambiguity, to correct or supplement any provision contained herein that may be defective or inconsistent with any other provisions
herein, or to make any other provisions in regard to matters or questions arising hereunder that the Company and EF Hutton may deem necessary
or desirable and that the Company and EF Hutton deem shall not adversely affect the interest of the Holders. All other modifications or
amendments shall require the written consent of and be signed by 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 Warrant.


 


9.3 Entire Agreement.
This Purchase Warrant (together with the other agreements and documents being delivered pursuant to or in connection with this Purchase
Warrant) 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.


 


9.4 Binding Effect.
This Purchase Warrant shall inure solely to the benefit of and shall be binding upon, the Holder and the Company and their permitted assignees,
respective successors, legal representative 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 Warrant or any provisions herein contained.


 


9.5 Governing Law; Submission
to Jurisdiction; Trial by Jury. This Purchase Warrant shall be governed by and construed in accordance with the law of the State of
New York. The Company hereby agrees that any action, proceeding or claim against it arising out of, or relating in any way to this Purchase
Warrant shall be brought and enforced in the Supreme Court of the State of New York sitting in the County of New York, or in the United
States District Court for the Southern District of New York, and irrevocably submits to the jurisdiction of such courts and the appellate
courts therefrom, 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 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. The Company (on its behalf and, to the extent permitted by applicable law, on behalf of its stockholders
and affiliates) and the Holder hereby irrevocably waive, to the fullest extent permitted by applicable law, any and all right to trial
by jury in any legal proceeding arising out of or relating to this Purchase Warrant or the transactions contemplated hereby.


 


9.6 Waiver, etc. The
failure of the Company or the Holder to at any time enforce any of the provisions of this Purchase Warrant 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 Warrant or any provision hereof or the right
of the Company or any Holder to thereafter enforce each and every provision of this Purchase Warrant. No waiver of any breach, non-compliance
or non-fulfillment of any of the provisions of this Purchase Warrant 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.


 


9.7 Execution in Counterparts.
This Purchase Warrant may be executed in one or more counterparts, and by the different parties hereto in separate counterparts, each
of which shall be deemed to be an original, but all of which taken together shall constitute one and the same agreement, and shall become
effective when one or more counterparts has been signed by each of the parties hereto and delivered to each of the other parties hereto.
Such counterparts may be delivered by facsimile transmission or other electronic transmission.


 


9.8 Exchange Agreement.
As a condition of the Holder’s receipt and acceptance of this Purchase Warrant, Holder agrees that, at any time prior to the complete
exercise of this Purchase Warrant by Holder, if the Company and EF Hutton enter into an agreement (“Exchange Agreement”)
pursuant to which they agree that all outstanding Purchase Warrants will be exchanged for securities or cash or a combination of both,
then Holder shall agree to such exchange and become a party to the Exchange Agreement.


 


[Signature Page Follows]


 




    	 	A-9	 



     


    

  


IN WITNESS WHEREOF,
the Company has caused this Purchase Warrant to be signed by its duly authorized officer as of the ____ day of _______, 2022. 


 


	 	CASTELLUM, INC.
	 	 
	 	By: 	         	 
	 	Name: Mark C. Fuller
	 	Title: Chief Executive Officer


 




    	 	A-10	 



     


    

  


[Form to be used to exercise Purchase Warrant]


 


Date: __________, 20___


 


The undersigned hereby elects
irrevocably to exercise the Purchase Warrant for ______ Shares of Common Stock (the “Shares”), of Castellum, Inc.,
a Nevada corporation (the “Company”), and hereby makes payment of $____ (at the rate of $____ per Share) in payment
of the Exercise Price pursuant thereto. Please issue the Shares as to which this Purchase Warrant is exercised in accordance with the
instructions given below and, if applicable, a new Purchase Warrant representing the number of Shares for which this Purchase Warrant
has not been exercised.


 


or


 


The undersigned hereby elects
irrevocably to convert its right to purchase Shares of the Company under the Purchase Warrant for ______ Shares, as determined in accordance
with the following formula:


 


	 	X	=	
    Y(A-B) 

    A
	
     

     



 


	Where,	 	 	 
	 	X	=	The number of Shares to be issued to Holder;
	 	Y	=	The number of Shares for which the Purchase Warrant is being exercised;
	 	A	=	The fair market value of one Share which is equal to $_____; and
	 	B	=	The Exercise Price which is equal to $______ per share
	 	 	 	 	 	 	 


The undersigned agrees and
acknowledges that the calculation set forth above is subject to confirmation by the Company and any disagreement with respect to the calculation
shall be resolved by the Company in its sole discretion.


 


Please issue the Shares as
to which this Purchase Warrant is exercised in accordance with the instructions given below and, if applicable, a new Purchase Warrant
representing the number of Shares for which this Purchase Warrant has not been exercised.


 


Signature _______________________________________


 


Signature Guaranteed ______________________________


 


INSTRUCTIONS FOR REGISTRATION OF SECURITIES


 


	Name: 	 	 
	 	(Print in Block Letters)	 


 


	Address: 	 	 
	 	 	 
	 	 	 
	 	 	 
	 	 	 


 


NOTICE: The signature to this
form must correspond with the name as written upon the face of the Purchase Warrant 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.


 


[Form to be used to assign Purchase Warrant]


 




    	 	A-11	 



     


    

  


ASSIGNMENT


 


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


 


FOR VALUE RECEIVED, __________________ does hereby
sell, assign and transfer unto______________ the right to purchase _______________ shares, par value $0.001 per share (the “Shares”),
of the common stock of Castellum, Inc., (collectively with its subsidiaries and affiliates, including, without limitation, all entities
disclosed or described in the Registration Statement as being subsidiaries (the “Company”), evidenced by the Purchase
Warrant and does hereby authorize the Company to transfer such right on the books of the Company.


 


Dated: __________, 20__


 


	Signature 	 	 


 


	Signature Guaranteed 	 	 


 


NOTICE: The signature to this form must correspond
with the name as written upon the face of the within Purchase Warrant 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.


 




    	 	A-12