Exhibit
4.1


 


NUMBER
UNITS


U-[●]


 


SEE REVERSE
FOR CERTAIN


DEFINITIONS


CUSIP
42588J 209


 


HENNESSY
CAPITAL ACQUISITION CORP. II


 


UNITS
CONSISTING OF ONE SHARE OF COMMON STOCK AND ONE WARRANT TO


PURCHASE
ONE-HALF OF ONE SHARE OF COMMON STOCK


 


THIS CERTIFIES
THAT                                         is
the owner of                     Units.


 


Each Unit
(“Unit”) consists of one (1) share of common stock, par value $0.0001 per share (“Common
Stock”), of Hennessy Capital Acquisition Corp. II, a Delaware corporation (the “Company”),
and one warrant (the “Warrant”). Each Warrant entitles the holder to purchase one-half (1/2) of
one share (subject to adjustment) of Common Stock for $5.75 per half 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”), or (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 “Expiration
Date”). The Common Stock and Warrants comprising the Units represented by this certificate are not transferable
separately prior to             , 20            ,
unless UBS Securities LLC elects to allow separate trading earlier, 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 offering and issuing a press release announcing when separate trading will begin. The terms
of the Warrants are governed by a Warrant Agreement, dated as of             ,
2015, 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 17 Battery Place, 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.


 


Witness
the facsimile signature of its duly authorized officers.


 


	 	 	 
	Secretary	 	President


 






    	 



    	 



    

 





Hennessy
Capital Acquisition Corp. II


 


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:


 


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

(State)




 


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


 


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)


 


 





 



 


 





 






	 	 	 	 	 
	 	 	 	 	 


 


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


 


                        
                                         
    Attorney to transfer the said Units on the books of the within named Corporation with 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) 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).	 	 


 


In each
case, as more fully described in the Corporation’s final prospectus dated             ,
2015, 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 the Corporation redeems the shares of common
stock sold in its initial public offering and liquidates because it does not consummate an initial business combination by __________,
20__ or if the holder(s) seek(s) to redeem for cash his, her or its respective shares of common stock in connection with a tender
offer (or proxy solicitation, solely in the event the Corporation 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.