Exhibit 4.3


 


	
    NUMBER

    MCAER
	RIGHTS


 


MOUNTAIN CREST ACQUISITION CORP. III


 


INCORPORATED UNDER THE LAWS OF THE DELAWARE


 


RIGHT


 


SEE REVERSE FOR


CERTAIN DEFINITIONS


 


CUSIP 62402U 115


 


THIS CERTIFIES THAT, for value received


 


is the registered holder of a right or rights
(each, a “Right”) to automatically receive one-tenth of one share of common stock, $0.0001 par value (“Common Stock”),
of Mountain Crest Acquisition Corp. III (the “Company”) for each Right evidenced by this Rights Certificate on the Company’s
completion of an initial business combination (as defined in the prospectus relating to the Company’s initial public offering (“Prospectus”))
upon surrender of this Right Certificate pursuant to the Rights Agreement between the Company and Continental Stock Transfer & Trust
Company, as Rights Agent. In no event will the Company be required to net cash settle any Right.


 


Upon liquidation of the Company in the event an
initial business combination is not consummated during the required period as identified in the Company’s Amended and Restated Articles
of Incorporation, the Right shall expire and be worthless. The holder of a Right shall have no right or interest of any kind in the Company’s
trust account (as defined in the Prospectus).


 


Upon due presentment for registration of transfer
of the Right Certificate at the office or agency of the Rights Agent, a new Right Certificate or Right Certificates of like tenor and
evidencing in the aggregate a like number of Rights shall be issued to the transferee in exchange for this Right Certificate, without
charge except for any applicable tax or other governmental charge. The Company shall not issue fractional shares upon exchange of Rights.
The Company reserves the right to deal with any fractional entitlement at the relevant time in any manner (as provided in the Rights Agreement).


 


The Company and the Rights Agent may deem and
treat the registered holder as the absolute owner of this Right Certificate (notwithstanding any notation of ownership or other writing
hereon made by anyone), for the purpose of any conversion hereof, of any distribution to the registered holder, and for all other purposes,
and neither the Company nor the Right Agent shall be affected by any notice to the contrary.


 


This Right does not entitle the registered holder
to any of the rights of a shareholder of the Company.


 


	Dated:	 	 
	 	 	 
	CHAIRMAN	 	CHIEF FINANCIAL OFFICER
	 	 	 
	Continental Stock Transfer & Trust Company, as Rights Agent	 	 


  






     


     


    

 


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:


 


	TEN COM	—	as tenants in common	 	UNIF GIFT MIN ACT	—	 	Custodian	 
	 	 	 	 	 	 	(Cust)	 	(Minor)
	TEN ENT	—	as tenants by the entireties	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 
	JT TEN	—	as joint tenants with right of survivorship and not as tenants in common	 	 	under Uniform Gifts to Minors Act
	 	 	 	 	(State)


 


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


 


Mountain Crest Acquisition Corp. III


 


The Company will furnish without
charge to each shareholder who so requests the powers, designations, preferences and relative, participating, optional or other special
rights of each class of shares or series thereof of the Company and the qualifications, limitations, or restrictions of such preferences
and/or rights. This certificate and the rights represented thereby are issued and shall be held subject to all the provisions of the Articles
of Incorporation and all amendments thereto and resolutions of the Board of Directors providing for the issue of shares of Common Stock
(copies of which may be obtained from the secretary of the Company), to all of which the holder of this certificate by acceptance hereof
assents.


 


For value received, ___________________________
hereby sell, assign and transfer unto


 


	PLEASE INSERT SOCIAL SECURITY OR 

OTHER

IDENTIFYING NUMBER OF ASSIGNEE	 
	 	 
	 	 


 


	(PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)
	 
	 
	 
	 
	 


rights represented by the within Certificate,
and do hereby irrevocably constitute and appoint 


 


____________________________________________________________________________ Attorney
to transfer said rights on the books of the within named Company will full power of substitution in the premises. 


 


	Dated	 	 	 	 
	 	 	 	 	 
	 	 	 	 	 
	 	 	 	Notice:	The signature to this assignment
    must correspond with the name as written upon the face of the certificate in every particular, without alteration or enlargement
    or any change whatever.





 


Signature(s) Guaranteed:


 





	 	 
	THE SIGNATURE(S) SHOULD 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).	 


 


The holder of this certificate shall have no right
or interest of any kind in or to the funds held in the Company’s trust account (as defined in the Prospectus).