Exhibit 4.2


 


NUMBER





	C- 	 	SHARES









 


SEE REVERSE FOR


CERTAIN DEFINITIONS


 


CUSIP 822821 104


 


SPECIMEN CLASS A COMMON
STOCK CERTIFICATE


 


SHELTER ACQUISITION
CORPORATION I


 


INCORPORATED UNDER THE
LAWS OF THE STATE OF DELAWARE

CLASS A COMMON STOCK


 


This Certifies that ___________________________is the owner
of _______________


 


FULLY PAID AND NON-ASSESSABLE SHARES
OF THE PAR VALUE OF $0.0001 EACH OF THE CLASS A COMMON STOCK OF SHELTER ACQUISITION CORPORATION I (THE
“COMPANY”)


 


subject to the Company’s amended and
restated certificate of incorporation, as the same may be amended from time to time, and transferable on the books of the Company
in person or by duly authorized attorney upon surrender of this certificate properly endorsed.


 


The Company will be forced to redeem all
of its shares of Class A common stock if it is unable to complete a business combination within the period set forth in the Company’s
amended and restated certificate of incorporation, as the same may be amended from time to time, all as more fully described in
the Company’s final prospectus dated       , 2021.


 


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


 


Witness the seal of the Company and the
facsimile signatures of its duly authorized officers.


 


Dated: ___________


 


	Chief Executive Officer	[Corporate Seal]	Chief Financial Officer
	 	Delaware	 





 




    


     


    

 


SHELTER ACQUISITION CORPORATION I


 


The Company will furnish without charge to each stockholder
who so requests 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.
This certificate and the shares represented thereby are issued and shall be held subject to all the provisions of the Company’s
amended and restated certificate of incorporation, as the same may be amended from time to time and resolutions of the Board of
Directors providing for the issue of securities (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.


 


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	 
	TEN ENT	—	as tenants by the entireties	 	 	(Cust)	 	(Minor)
	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.


 




    2


     


    




 


For value received,                                       
  hereby sells, assigns and transfers unto





 





 






(PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER(S)
OF ASSIGNEE(S))


 





 











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


 








 











Shares of the capital
stock represented by the within Certificate, and does hereby irrevocably constitute and appoint


 





 











Attorney to transfer
the said stock on the books of the within named Company with full power of substitution in the premises.


 








 



 


Dated:__________





 





	 	 
	 	Stockholder











 





 






NOTICE: THE SIGNATURE(S) 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:	 
	 	 
	By	 
	 	 
	 	 
	 	 
	 	 









 


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).





 


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 its initial public offering only in the event that (i) the Company
redeems the shares of Class A common stock sold in its initial public offering and liquidates because it does not consummate an
initial business combination within the period of time set forth in the Company’s amended and restated certificate of incorporation,
as the same may be amended from time to time, (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 to
modify the substance or timing of the Company’s obligation to provide holders of the Class A common stock the right to have
their shares redeemed in connection with the Company’s initial business combination or to redeem 100% of the Class A common
stock if the Company does not complete its initial business combination within the time period set forth therein or with respect
to any other provision relating to the rights of holders of the Class A common stock 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.