Specimen Unit Certificate

Exhibit 4.1

CUSIP 716421 201

UNITS CONSISTING OF ONE SHARE OF COMMON STOCK AND

ONE-HALF OF ONE WARRANT

THIS CERTIFIES THAT__________________________________________________________________

is the owner of_________________________________________________________________Units.

Each Unit (“Unit”) consists of one (1) share of common stock, par value $0.001 per share (“Common Stock”), of Petra Acquisition, Inc., a Delaware corporation (the “Company”), and one-half of one warrant (“Warrant”). Each whole Warrant entitles the holder to purchase one share of Common Stock for $11.50 per share (subject to adjustment). Only whole Warrants are exercisable. Each whole Warrant will become exercisable on the later of (i) 30 days after the Company’s completion of an initial merger, capital stock exchange, asset acquisition, or other similar business combination with one or more businesses or entities (a “Business Combination”) and (ii) 12 months from the closing of the Company’s initial public offering (“IPO”), and will expire unless exercised before 5:00 p.m., New York City Time, on the fifth anniversary of the completion of an initial Business Combination, or earlier upon redemption or liquidation. The Common Stock and Warrant(s) comprising the Unit(s) represented by this certificate are not transferable separately until ninety days following the effective date of the registration statement on Form S-1 filed with the Securities and Exchange Commission (“SEC”) in connection with the Company’s IPO, unless LifeSci Capital LLC informs the Company of its decision to allow earlier separate trading, except that in no event will the Common Stock and Warrants be separately tradeable until the Company has filed a Current Report on Form 8-K with the SEC containing an audited balance sheet reflecting the Company’s receipt of the gross proceeds of its IPO and issued a press release announcing when such separate trading will begin. The terms of the Warrants are governed by a Warrant Agreement, dated as of ____, 2020, 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, 30^th 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.

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

By

Petra Acquisition, Inc.

The Company will furnish without charge to each shareholder 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 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 Company will full power of substitution in the premises.

Signature(s) Guaranteed:

The holder(s) of this certificate shall be entitled to receive a pro-rata portion of the funds from the trust account with respect to the common stock underlying this certificate only in the event that (i) the Company is forced to liquidate 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 (the “Charter”) or (ii) if the holder seeks to convert his shares upon consummation of, or sell his shares in a tender offer in connection with, an initial business combination or in connection with certain amendments to the Charter. In no other circumstances shall the holder(s) have any right or interest of any kind in or to the trust account.