Specimen Unit Certificate

Exhibit 4.1

CUSIP [●]

SEE REVERSE FOR CERTAIN DEFINITIONS

CRIXUS BH3 ACQUISITION COMPANY

UNITS CONSISTING OF ONE SHARE OF CLASS A COMMON STOCK AND ONE-

HALF OF ONE WARRANT, EACH WHOLE WARRANT ENTITLING THE HOLDER

TO PURCHASE ONE SHARE OF CLASS A COMMON STOCK

THIS CERTIFIES THAT __________ is the owner of _________ Units.

Each Unit (“Unit”) consists of one (1) share of Class A common stock, par value $0.0001 per share (“Common Stock”), of Crixus BH3 Acquisition Company, a Delaware corporation (the “Company”), and one-half of one redeemable warrant (each whole warrant, a “Warrant”). Each whole Warrant entitles the holder to purchase one (1) share (subject to adjustment) of Common Stock for $11.50 per share (subject to adjustment). Each Warrant will become exercisable on the later of (i) thirty (30) days after the Company’s completion of a merger, capital stock exchange, asset acquisition, stock purchase, reorganization or other similar business combination with one or more businesses (each a “Business Combination”) and (ii) twelve (12) months from the closing of the Company’s initial public offering, and will expire unless exercised before 5:00 p.m., New York City Time, on the date that is five (5) years after the date on which the Company completes its initial Business Combination, or earlier upon redemption or liquidation. The Common Stock and Warrants comprising the Units represented by this certificate are not transferable separately prior to __________, 2021, unless the representative of the underwriters elects to allow earlier separate trading, subject to the Company’s filing of a Current Report on Form 8-K with the Securities and Exchange Commission containing an audited balance sheet reflecting the Company’s receipt of the gross proceeds of the Company’s initial public offering and issuing a press release announcing when separate trading will begin. No fractional warrants will be issued upon separation of the Units and only whole Warrants will trade. The terms of the Warrants are governed by a Warrant Agreement, dated as of __________, 2021, between the Company and Continental Stock Transfer & Trust Company, as Warrant Agent, and are subject to the terms and provisions contained therein, all of which terms and provisions the holder of this certificate consents to by acceptance hereof. Copies of the Warrant Agreement are on file at the office of the Warrant Agent at 1 State Street, 30th Floor, New York, New York 10004, and are available to any Warrant holder on written request and without cost.

This certificate is not valid unless countersigned by the Transfer Agent and Registrar of the Company.

This certificate shall be governed by and construed in accordance with the internal laws of the State of New York.

Witness the facsimile signatures of the duly authorized officers of the Company.

Crixus BH3 Acquisition Company

The Company will furnish without charge to each unitholder who so requests, a statement of the powers, designations, preferences and relative, participating, optional or other special rights of each class of stock or series thereof of the Company and the qualifications, limitations, or restrictions of such preferences and/or rights.

The following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to applicable laws or regulations:

Additional abbreviations may also be used though not in the above list.

For value received, ___________ hereby sells, assigns and transfers unto

________________Units represented by the within Certificate, and does hereby irrevocably constitute and appoint______________ Attorney to transfer the said Units on the books of the within named Company with full power of substitution in the premises.

Signature(s) Guaranteed:

THE SIGNATURE(S) MUST BE GUARANTEED BY

AN ELIGIBLE GUARANTOR INSTITUTION (BANKS,

STOCKBROKERS, SAVINGS AND LOAN

ASSOCIATIONS AND CREDIT UNIONS WITH

MEMBERSHIP IN AN APPROVED SIGNATURE

GUARANTEE MEDALLION PROGRAM, PURSUANT

TO S.E.C. RULE 17Ad-15 (OR ANY SUCCESSOR

RULE) UNDER THE SECURITIES EXCHANGE ACT

OF 1934, AS AMENDED).

In each case, as more fully described in the Company’s final prospectus dated __________, 2021, the holder(s) of this certificate shall be entitled to receive a pro-rata portion of certain funds held in the trust account established in connection with the Company’s initial public offering only in the event that (i) the Company redeems the shares of Class A common stock sold in the Company’s initial public offering and liquidates because it does not consummate an initial business combination by the date set forth in the Company’s amended and restated certificate of incorporation, (ii) the Company redeems the shares of Class A common stock sold in its initial public offering in connection with a stockholder vote to amend the Company’s amended and restated certificate of incorporation (a) to modify the substance or timing of the Company’s obligation to allow redemption in connection with the Company’s initial business combination or to redeem 100% of the Class A common stock if it does not consummate an initial business combination by the date set forth in the Company’s amended and restated certificate of incorporation or (b) with respect to any other provisions relating to stockholders’ rights or pre-initial business combination activity, or (iii) if the holder(s) seek(s) to redeem for cash his, her or its respective shares of Class A common stock in connection with a tender offer (or proxy solicitation, solely in the event the Company seeks stockholder approval of the proposed initial business combination) setting forth the details of a proposed initial business combination. In no other circumstances shall the holder(s) have any right or interest of any kind in or to the trust account.