Document:

Exhibit 4.3

 

THE REGISTERED HOLDER OF THIS PURCHASE
OPTION BY ITS ACCEPTANCE HEREOF AGREES THAT IT WILL NOT SELL, TRANSFER OR ASSIGN THIS PURCHASE OPTION EXCEPT AS HEREIN PROVIDED
AND THE REGISTERED HOLDER OF THIS PURCHASE OPTION AGREES THAT IT WILL NOT SELL, TRANSFER, ASSIGN, PLEDGE OR HYPOTHECATE THIS PURCHASE
OPTION OR CAUSE IT TO BE THE SUBJECT OF ANY HEDGING, SHORT SALE, DERIVATIVE, PUT, OR CALL TRANSACTION THAT WOULD RESULT IN THE
EFFECTIVE ECONOMIC DISPOSITION OF THE PURCHASE OPTION BY ANY PERSON FOR A PERIOD OF ONE HUNDRED EIGHTY DAYS FOLLOWING THE EFFECTIVE
DATE (AS DEFINED HEREIN) TO ANYONE OTHER THAN TO (I) CHARDAN CAPITAL MARKETS, LLC (“CHARDAN”) OR AN UNDERWRITER
OR SELECTED DEALER PARTICIPATING IN THE OFFERING OR (II) AN OFFICER OR PARTNER OF CHARDAN OR OF ANY SUCH UNDERWRITER OR SELECTED
DEALER AND IN ACCORDANCE WITH FINRA RULE 5110(G)(2).

 

THIS PURCHASE OPTION IS NOT EXERCISABLE
PRIOR TO THE LATER OF THE CONSUMMATION BY ORISUN ACQUISITION CORP. (THE “COMPANY”) OF A MERGER, SHARE
EXCHANGE, ASSET ACQUISITION, RECAPITALIZATION, REORGANIZATION OR OTHER SIMILAR BUSINESS COMBINATION (THE “BUSINESS
COMBINATION”) (AS DESCRIBED MORE FULLY IN THE COMPANY’S REGISTRATION STATEMENT (DEFINED HEREIN)) AND FEBRUARY
2, 2020. VOID AFTER 5:00 P.M. NEW YORK CITY LOCAL TIME, ON THE EXPIRATION DATE (DEFINED HEREIN).

 

UNIT PURCHASE OPTION

FOR THE PURCHASE OF

UP TO 300,000 UNITS

OF

ORISUN ACQUISITION CORP.

 

1.
PURCHASE OPTION.

 

THIS CERTIFIES THAT, in consideration of
$100.00 duly paid by or on behalf of Chardan Capital Markets, LLC (the “Holder”), as registered owner
of this Purchase Option, to Orisun Acquisition Corp. (the “Company”), Holder is entitled, at any time
or from time to time upon the later of the consummation of a Business Combination or February 2, 2020 (the “Commencement
Date”), and at or before 5:00 p.m., New York City local time, on the five year anniversary of the effective date
(the “Effective Date”) of the Company’s registration statement (the “Registration Statement”)
pursuant to which Units are offered for sale to the public in the Company’s initial public offering (the “Offering”),
but not thereafter (the “Expiration Date”), to subscribe for, purchase and receive, in whole or in part,
up to Three Hundred Thousand (300,000) units (“Units”) of the Company, each Unit consisting of one (1)
share of common stock, par value $0.00001 per share, of the Company (“Share(s)”), one (1) warrant (“Warrant(s)”),
each Warrant entitling the holder thereof to purchase one-half (1/2) of one Share and one (1) right to receive one-tenth (1/10)
of a Share upon the consummation of a Business Combination (“Right(s)”). Each Right has the same terms
as the rights included in the units being registered for sale to the public by way of the Registration Statement (“Public
Rights”). Each Warrant has the same terms as the warrants included in the Units being registered for sale to the
public by way of the Registration Statement (the “Public Warrants”). Notwithstanding anything to the
contrary, the original Holder of this Purchase Option agrees that it will not be permitted to exercise his Purchase Option or the
Warrants underlying this Purchase Option after the five year anniversary of the Effective Date. During the period ending on the
Expiration Date, the Company agrees not to take any action that would terminate the Purchase Option. This Purchase Option is initially
exercisable at $11.50 per Unit so purchased; provided, however, that upon the occurrence of any of the events specified
in Section 6 hereof, the rights granted by this Purchase Option, including the exercise price per Unit and the number of
Units (and Shares, Warrants and Rights) to be received upon such exercise, shall be adjusted as therein specified. The term “Exercise
Price” shall mean the initial exercise price or the adjusted exercise price, depending on the context.

 

2.
EXERCISE OF PURCHASE OPTION.

 

2.1 Exercise Form. In order to exercise
this Purchase Option, the exercise form attached hereto must be duly executed and completed and delivered to the Company, together
with this Purchase Option and payment of the Exercise Price for the Units being purchased payable in cash or by certified check
or official bank check or pursuant to Section 2.3 hereof. If the subscription rights represented hereby shall not be exercised
at or before 5:00 p.m., New York City local time, on the Expiration Date, this Purchase Option shall become and be void without
further force or effect, and all rights represented hereby shall cease and expire.

 

     

     

    

 

2.2 Legend. Each certificate for
the securities purchased under this Purchase Option shall bear a legend as follows, unless such securities have been registered
under the Securities Act of 1933, as amended (“Act”):

 

“The securities represented by this certificate
have not been registered under the Securities Act of 1933, as amended (“Act”) or the laws of applicable states or other
jurisdictions. The securities may not be offered for sale, sold or otherwise transferred except pursuant to an effective registration
statement under the Act, or pursuant to an exemption from registration under the Act and applicable laws of states or other jurisdictions.”

 

2.3 Cashless Exercise.

 

2.3.1 Determination of Amount. In lieu
of the payment of the Exercise Price multiplied by the number of Units for which this Purchase Option is exercisable (and in lieu
of being entitled to receive Shares and Warrants) in the manner required by Section 2.1, and subject to Section 6.1
hereof, the Holder shall have the right (but not the obligation) to convert any exercisable but unexercised portion of this Purchase
Option into Units (“Cashless Exercise Right”) as follows: upon exercise of the Cashless Exercise Right,
the Company shall deliver to the Holder (without payment by the Holder of any of the Exercise Price in cash) that number of Units
(or that number of Shares, Warrants and Rights comprising that number of Units) equal to the number of Units to be exercised multiplied
by the quotient obtained by dividing (x) the “Value” (as defined below) of the portion of the Purchase Option being
converted by (y) the Current Market Value (as defined below). The “Value” of the portion of the Purchase
Option being converted shall equal the remainder derived from subtracting (a) (i) the Exercise Price multiplied by (ii) the number
of Units underlying the portion of this Purchase Option being converted from (b) the Current Market Value of a Unit multiplied
by the number of Units underlying the portion of the Purchase Option being converted. As used herein, the term “Current
Market Value” per Unit at any date means: (A) in the event that the Units, Shares, Public Rights and Public Warrants
are still trading, (i) if the Units are listed on a national securities exchange, the average reported last sale price of the Units
in the principal trading market for the Units as reported by the exchange, as the case may be, for the three trading days preceding
the date in question; or (ii) if the Units are not listed on a national securities exchange, but is traded in the over-the-counter
market, the average reported last sale price for Units for the three trading days preceding the date in question for which such
quotations are reported by the OTC Markets Group Inc., or similar publisher of such quotations; (B) in the event that the Units
are not still trading but the Shares, Public Rights, and Public Warrants underlying the Units are still trading, the aggregate
of (i) the product of (x) the Current Market Price of the Share and (y) the number of the Shares underlying one Unit (which shall
include the portion of a Share the holder of a Unit would automatically receive in connection with the Right included in each such
Unit), plus (ii) the product of (x) the Current Market Price of the Public Warrants and (y) the number of Warrants included in
one Unit; or (C) in the event that neither the Units nor the Public Warrants are still trading, the aggregate of (i) the product
of (x) the Current Market Price of the Shares and (y) the number of the Shares underlying one Unit (which shall include the portion
of a Share the holder of a Unit would automatically receive in connection with the Right included in each such Unit), plus (ii)
the remainder derived from subtracting (x) the exercise price of the Warrants multiplied by the number of Shares issuable upon
exercise of the Warrants underlying one Unit from (y) the product of (aa) the Current Market Price of the Shares multiplied by
(bb) the number of Shares underlying the Warrants included in each such Unit. The “Current Market Price” shall mean
(i) if the Shares (or Public Warrants, as the case may be) are listed on a national securities exchange, the average reported last
sale price of the Shares (or Public Warrants) in the principal trading market for the Share (or Public Warrants) as reported by
the exchange, as the case may be, for the three trading days preceding the date in question; (ii) if the Shares (or Public Warrants)
are not listed on a national securities exchange, but are traded in the over-the-counter market, the average reported last sale
price for the Share (or Public Warrants) for the three (3) trading days preceding the date in question for which such quotations
are reported by the OTC Markets Group Inc., or similar publisher of such quotations; and (iii) if the fair market value of the
Share cannot be determined pursuant to clause (i) or (ii) above, such price as the Board of Directors of the Company shall determine,
in good faith. In the event the Public Warrants have expired and are no longer exercisable, no “Value” shall be attributed
to the Warrants underlying this Purchase Option.

 

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2.3.2 Mechanics of Cashless Exercise.
The Cashless Exercise Right may be exercised by the Holder on any business day on or after the Commencement Date and not later
than the Expiration Date by delivering the Purchase Option with the duly executed exercise form attached hereto with the cashless
exercise section completed to the Company, exercising the Cashless Exercise Right and specifying the total number of Units the
Holder will purchase pursuant to such Cashless Exercise Right

 

2.4 No Obligation to Net Cash Settle.
Notwithstanding anything to the contrary contained in this Purchase Option, in no event will the Company be required to net cash
settle the exercise of the Purchase Option or Warrants underlying the Purchase Option. The holder of the Purchase Option and Warrants
underlying the Purchase Option will not be entitled to exercise the Purchase Option or the Warrants underlying such Purchase Option
unless it exercises such Purchase Option pursuant to the Cashless Exercise Right or a registration statement is effective, or an
exemption from the registration requirements is available at such time and, if the holder is not able to exercise the Purchase
Option or underlying Warrants, the Purchase Option and/or the underlying Warrants, as applicable, will expire worthless.

 

3.
TRANSFER OF PURCHASE OPTION.

 

3.1 General Restrictions. The registered
Holder of this Purchase Option, by its acceptance hereof, agrees that it will not sell, transfer, assign, pledge or hypothecate
this Purchase Option (or the Shares, Rights and Warrants underlying this Purchase Option), or cause the Purchase Option (or the
Shares, Rights and Warrants underlying this Purchase Option) to be the subject of any hedging, short sale, derivative, put, or
call transaction that would result in the effective economic disposition of the Purchase Option by any person, for a period of
180 days (pursuant to Rule 5110(g)(1) of the Conduct Rules of the Financial Industry Regulatory Authority (FINRA))
following the Effective Date to anyone other than (i) Chardan or an underwriter or selected dealer in connection with the Offering,
or (ii) a bona fide officer or partner of Chardan or of any such underwriter or selected dealer. On and after the 181st day following
the Effective Date, transfers to others may be made subject to compliance with or exemptions from applicable securities laws. In
order to make any permitted assignment, the Holder must deliver to the Company the assignment form attached hereto duly executed
and completed, together with the Purchase Option and payment of all transfer taxes, if any, payable in connection therewith. The
Company shall within 5 business days transfer this Purchase Option on the books of the Company and shall execute and deliver a
new Purchase Option of like tenor to the appropriate assignee(s) expressly evidencing the right to purchase the aggregate number
of Units purchasable hereunder or such portion of such number as shall be contemplated by any such assignment.

 

3.2 Restrictions Imposed by the Act.
The securities evidenced by this Purchase Option shall not be transferred unless and until (i) the Company has received the opinion
of counsel for the Holder that the securities may be transferred pursuant to an exemption from registration under the Act and applicable
state securities laws, the availability of which is established to the reasonable satisfaction of the Company (the Company hereby
agreeing that the opinion of Ellenoff Grossman & Schole LLP shall be deemed satisfactory evidence of the availability of an
exemption), or (ii) a registration statement or a post-effective amendment to the Registration Statement relating to such securities
has been filed by the Company and declared effective by the Securities and Exchange Commission (the “Commission”)
and compliance with applicable state securities law has been established.

 

4.
NEW PURCHASE OPTION TO BE ISSUED.

 

4.1 Partial Exercise or Transfer.
Subject to the restrictions in Section 3 hereof, this Purchase Option may be exercised or assigned in whole or in part.
In the event of the exercise or assignment hereof in part only, upon surrender of this Purchase Option for cancellation, together
with the duly executed exercise or assignment form and funds sufficient to pay any Exercise Price (except to the extent that the
Holder elects to exercise this Purchase Option by means of a cashless exercise as provided in Section 2.3 above) and/or
transfer tax, the Company shall cause to be delivered to the Holder without charge a new Purchase Option of like tenor to this
Purchase Option in the name of the Holder evidencing the right of the Holder to purchase the number of Units purchasable hereunder
as to which this Purchase Option has not been exercised or assigned

 

4.2 Lost Certificate. Upon receipt
by the Company of evidence satisfactory to it of the loss, theft, destruction or mutilation of this Purchase Option and of reasonably
satisfactory indemnification or the posting of a bond, the Company shall execute and deliver a new Purchase Option of like tenor
and date. Any such new Purchase Option executed and delivered as a result of such loss, theft, mutilation or destruction shall
constitute a substitute contractual obligation on the part of the Company.

 

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5.
REGISTRATION RIGHTS.

 

5.1 Demand Registration.

 

5.1.1 Grant of Right. The Company,
upon written demand (“Initial Demand Notice”) of the Holder(s) of at least 51% of the Purchase Option
and/or the underlying Units and/or the underlying securities (“Majority Holders”), agrees to use its
best efforts to register (the “Demand Registration”) under the Act on one occasion, all or any portion
of the Purchase Option requested by the Majority Holders in the Initial Demand Notice and all of the securities underlying such
Purchase Option, including the Units, Shares, Warrants and the Shares underlying the Warrants and Rights (collectively, the “Registrable
Securities”). On such occasion, the Company will use its best efforts to file a registration statement or a post-effective
amendment to the Registration Statement covering the Registrable Securities as expeditiously as possible after receipt of the Initial
Demand Notice and use its best efforts to have such registration statement or post-effective amendment declared effective as soon
as possible thereafter. The demand for registration may be made at any time during a period of five years beginning on the Effective
Date. The Initial Demand Notice shall specify the number of shares of Registrable Securities proposed to be sold and the intended
method(s) of distribution thereof. The Company will notify all holders of the Purchase Option and/or Registrable Securities of
the demand within ten days from the date of the receipt of any such Initial Demand Notice. Each holder of Registrable Securities
who wishes to include all or a portion of such holder’s Registrable Securities in the Demand Registration (each such holder
including shares of Registrable Securities in such registration, a “Demanding Holder”) shall so notify
the Company within fifteen (15) days after the receipt by the holder of the notice from the Company. Upon any such request, the
Demanding Holders shall be entitled to have their Registrable Securities included in the Demand Registration, subject to Section
5.1.4. The Company shall not be required to effect more than one (1) Demand Registration under this Section 5.1 in respect
of all Registrable Securities.

 

5.1.2 Effective Registration. Notwithstanding
Section 5.1.5, a registration will not count as a Demand Registration until the registration statement filed with the Commission,
with respect to such Demand Registration, has been declared effective and the Company has complied with all of its obligations
under this Purchase Option with respect thereto.

 

5.1.3 Underwritten Offering. If the
Majority Holders so elect and such holders so advise the Company as part of the Initial Demand Notice, the offering of such Registrable
Securities pursuant to such Demand Registration shall be in the form of an underwritten offering. In such event, the right of any
holder to include its Registrable Securities in such registration shall be conditioned upon such holder’s participation in
such underwriting and the inclusion of such holder’s Registrable Securities in the underwriting to the extent provided herein.
All Demanding Holders proposing to distribute their securities through such underwriting shall enter into an underwriting agreement
in customary form with the underwriter or underwriters selected for such underwriting by the Majority Holders.

 

5.1.4 Reduction of Offering. If the
managing underwriter or underwriters for a Demand Registration that is to be an underwritten offering advises the Company and the
Demanding Holders in writing that the dollar amount or number of shares of Registrable Securities which the Demanding Holders desire
to sell, taken together with all other Shares or other securities which the Company desires to sell and the Shares, if any, as
to which registration has been requested pursuant to written contractual piggy-back registration rights held by other shareholders
of the Company who desire to sell, exceeds the maximum dollar amount or maximum number of shares that can be sold in such offering
without adversely affecting the proposed offering price, the timing, the distribution method, or the probability of success of
such offering (such maximum dollar amount or maximum number of shares, as applicable, the “Maximum Number of Shares”),
then the Company shall include in such registration: (i) first, the Registrable Securities as to which Demand Registration has
been requested by the Demanding Holders (pro rata in accordance with the number of shares that each such person has requested be
included in such registration, regardless of the number of shares held by each such person (such proportion is referred to herein
as “Pro Rata”)) that can be sold without exceeding the Maximum Number of Shares; (ii) second, to the
extent that the Maximum Number of Shares has not been reached under the foregoing clause (i), the Shares or other securities that
the Company desires to sell that can be sold without exceeding the Maximum Number of Shares; (iii) third, to the extent that the
Maximum Number of Shares has not been reached under the foregoing clauses (i) and (ii), the Shares or other securities registrable
pursuant to the terms of the Registration Rights Agreement between the Company and the initial investors in the Company and Chardan,
dated as of August 2, 2019 (the “Registration Rights Agreement” and such registrable securities, the
“Investor Securities”) as to which “piggy-back” registration has been requested by the holders
thereof, Pro Rata, that can be sold without exceeding the Maximum Number of Shares; and (iv) fourth, to the extent that the Maximum
Number of Shares has not been reached under the foregoing clauses (i), (ii), and (iii), the Shares or other securities for the
account of other persons that the Company is obligated to register pursuant to written contractual arrangements with such persons
and that can be sold without exceeding the Maximum Number of Shares.

 

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5.1.5 Withdrawal. If a majority-in-interest
of the Demanding Holders disapprove of the terms of any underwriting or are not entitled to include all of their Registrable Securities
in any offering, such majority-in-interest of the Demanding Holders may elect to withdraw from such offering by giving written
notice to the Company and the underwriter or underwriters of their request to withdraw prior to the effectiveness of the registration
statement filed with the Commission with respect to such Demand Registration. If the majority-in-interest of the Demanding Holders
withdraws from a proposed offering relating to a Demand Registration, then the Company does not have to continue its obligations
under Section 5.1, provided that, any such withdrawal will not count as the Demand Registration if the Demanding
Holders pay all of the Company’s out-of-pocket expenses, with respect to such withdrawn registration.

 

5.1.6 Terms. The Company shall bear
all fees and expenses attendant to registering the Registrable Securities, including the expenses of one legal counsel selected
by the Holders to represent them in connection with the sale of the Registrable Securities, but the Holders shall pay any and all
underwriting commissions. The Company agrees to use its reasonable best efforts to qualify or register the Registrable Securities
in such states as are reasonably requested by the Majority Holder(s); provided, however, that in no event shall the
Company be required to register the Registrable Securities in a state in which such registration would cause (i) the Company to
be obligated to qualify to do business in such state, or would subject the Company to taxation as a foreign corporation doing business
in such jurisdiction or (ii) the principal shareholders of the Company to be obligated to escrow their shares of capital stock
of the Company. The Company shall use its best efforts to cause any registration statement or post-effective amendment filed pursuant
to the demand rights granted under Section 5.1.1 to remain effective for a period of nine consecutive months from the effective
date of such registration statement or post-effective amendment.

 

5.2 Piggy-Back Registration.

 

5.2.1 Piggy-Back Rights. If at any
time during the seven year period commencing on the Effective Date the Company proposes to file a registration statement under
the Act with respect to an offering of equity securities, or securities or other obligations exercisable or exchangeable for, or
convertible into, equity securities, by the Company for its own account or for shareholders of the Company for their account (or
by the Company and by shareholders of the Company including, without limitation, pursuant to Section 5.1), other than a
registration statement (i) filed in connection with any employee stock option or other benefit plan, (ii) for an exchange offer
or offering of securities solely to the Company’s existing shareholders, (iii) for an offering of debt that is convertible
into equity securities of the Company or (iv) for a dividend reinvestment plan, then the Company shall (x) give written notice
of such proposed filing to the holders of Registrable Securities as soon as practicable but in no event less than ten (10) days
before the anticipated filing date, which notice shall describe the amount and type of securities to be included in such offering,
the intended method(s) of distribution, and the name of the proposed managing underwriter or underwriters, if any, of the offering,
and (y) offer to the holders of Registrable Securities in such notice the opportunity to register the sale of such number of shares
of Registrable Securities as such holders may request in writing within five (5) days following receipt of such notice (a “Piggy-Back
Registration”). The Company shall cause such Registrable Securities to be included in such registration and shall
use its best efforts to cause the managing underwriter or underwriters of a proposed underwritten offering to permit the Registrable
Securities requested to be included in a Piggy-Back Registration on the same terms and conditions as any similar securities of
the Company and to permit the sale or other disposition of such Registrable Securities in accordance with the intended method(s)
of distribution thereof. All holders of Registrable Securities proposing to distribute their securities through a Piggy-Back Registration
that involves an underwriter or underwriters shall enter into an underwriting agreement in customary form with the underwriter
or underwriters selected for such Piggy-Back Registration

 

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5.2.2 Reduction of Offering. If the
managing underwriter or underwriters for a Piggy-Back Registration that is to be an underwritten offering advises the Company and
the holders of Registrable Securities in writing that the dollar amount or number of Shares which the Company desires to sell,
taken together with Shares, if any, as to which registration has been demanded pursuant to written contractual arrangements with
persons other than the holders of Registrable Securities hereunder, the Registrable Securities as to which registration has been
requested under this Section 5.2, and the Shares, if any, as to which registration has been requested pursuant to the written
contractual piggy-back registration rights of other shareholders of the Company, exceeds the Maximum Number of Shares, then the
Company shall include in any such registration:

 

(a) If the registration
is undertaken for the Company’s account: (A) first, Shares or other securities that the Company desires to sell that can
be sold without exceeding the Maximum Number of Shares; (B) second, to the extent that the Maximum Number of Shares has not been
reached under the foregoing clause (A), the Shares or other securities, if any, comprised of Registrable Securities and Investor
Securities, as to which registration has been requested pursuant to the applicable written contractual piggy-back registration
rights of such security holders, Pro Rata, that can be sold without exceeding the Maximum Number of Shares; and (C) third, to the
extent that the Maximum Number of shares has not been reached under the foregoing clauses (A) and (B), the Shares or other securities
for the account of other persons that the Company is obligated to register pursuant to written contractual piggy-back registration
rights with such persons and that can be sold without exceeding the Maximum Number of Shares;

 

(b) If the registration
is a “demand” registration undertaken at the demand of holders of Investor Securities, (A) first, the Shares or other
securities for the account of the demanding persons, Pro Rata, that can be sold without exceeding the Maximum Number of Shares;
(B) second, to the extent that the Maximum Number of Shares has not been reached under the foregoing clause (A), the Shares or
other securities that the Company desires to sell that can be sold without exceeding the Maximum Number of Shares; (C) third, to
the extent that the Maximum Number of Shares has not been reached under the foregoing clauses (A) and (B), the shares of Registrable
Securities, Pro Rata, as to which registration has been requested pursuant to the terms hereof, that can be sold without exceeding
the Maximum Number of Shares; and (D) fourth, to the extent that the Maximum Number of Shares has not been reached under the foregoing
clauses (A), (B) and (C), the Shares or other securities for the account of other persons that the Company is obligated to register
pursuant to written contractual arrangements with such persons, that can be sold without exceeding the Maximum Number of Shares;
and

 

(c) If the registration
is a “demand” registration undertaken at the demand of persons other than either the holders of Registrable Securities
or of Investor Securities, (A) first, the Shares or other securities for the account of the demanding persons that can be sold
without exceeding the Maximum Number of Shares; (B) second, to the extent that the Maximum Number of Shares has not been reached
under the foregoing clause (A), the Shares or other securities that the Company desires to sell that can be sold without exceeding
the Maximum Number of Shares; (C) third, to the extent that the Maximum Number of Shares has not been reached under the foregoing
clauses (A) and (B), collectively the Shares or other securities comprised of Registrable Securities and Investor Securities, Pro
Rata, as to which registration has been requested pursuant to the terms hereof and of the Registration Rights Agreement, as applicable,
that can be sold without exceeding the Maximum Number of Shares; and (D) fourth, to the extent that the Maximum Number of Shares
has not been reached under the foregoing clauses (A), (B) and (C), the Shares or other securities for the account of other persons
that the Company is obligated to register pursuant to written contractual arrangements with such persons, that can be sold without
exceeding the Maximum Number of Shares.

 

5.2.3 Withdrawal. Any holder of Registrable
Securities may elect to withdraw such holder’s request for inclusion of Registrable Securities in any Piggy-Back Registration
by giving written notice to the Company of such request to withdraw prior to the effectiveness of the registration statement. The
Company (whether on its own determination or as the result of a withdrawal by persons making a demand pursuant to written contractual
obligations) may withdraw a registration statement at any time prior to the effectiveness of the registration statement. Notwithstanding
any such withdrawal, the Company shall pay all expenses incurred by the holders of Registrable Securities in connection with such
Piggy-Back Registration as provided in Section 5.2.4.

 

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5.2.4 Terms. The Company shall bear
all fees and expenses attendant to registering the Registrable Securities, including the expenses of one legal counsel selected
by the Holders to represent them in connection with the sale of the Registrable Securities but the Holders shall pay any and all
underwriting commissions related to the Registrable Securities. In the event of such a proposed registration, the Company shall
furnish the then Holders of outstanding Registrable Securities with not less than fifteen days written notice prior to the proposed
date of filing of such registration statement. Such notice to the Holders shall continue to be given for each applicable registration
statement filed (during the period in which the Purchase Option is exercisable) by the Company until such time as all of the Registrable
Securities have been registered and sold. The Holders of the Registrable Securities shall exercise the “piggy-back”
rights provided for herein by giving written notice within ten days of the receipt of the Company’s notice of its intention
to file a registration statement. The Company shall use its best efforts to cause any registration statement filed pursuant to
the above “piggyback” rights to remain effective for at least nine months from the date that the Holders of the Registrable
Securities are first given the opportunity to sell all of such securities.

 

5.3 General Terms.

 

5.3.1 Indemnification. The Company
shall, to the fullest extent permitted by applicable law, indemnify the Holder(s) of the Registrable Securities to be sold pursuant
to any registration statement hereunder and each person, if any, who controls such Holders within the meaning of Section 15 of
the Act or Section 20(a) of the Securities Exchange Act of 1934, as amended (“Exchange Act”), against
all loss, claim, damage, expense or liability (including all reasonable attorneys’ fees and other expenses reasonably incurred
in investigating, preparing or defending against litigation, commenced or threatened, or any claim whatsoever whether arising out
of any action between the underwriter and the Company or between the underwriter and any third party or otherwise) to which any
of them may become subject under the Act, the Exchange Act or otherwise, arising from such registration statement but only to the
same extent and with the same effect as the provisions pursuant to which the Company has agreed to indemnify the underwriters contained
in Section 5 of the Underwriting Agreement between the Company, Chardan and the other underwriters named therein dated the Effective
Date (“Underwriting Agreement”). The Holder(s) of the Registrable Securities to be sold pursuant to such
registration statement, and their successors and assigns, shall severally, and not jointly, indemnify the Company, its officers
and directors and each person, if any, who controls the Company within the meaning of Section 15 of the Act or Section 20(a) of
the Exchange Act, against all loss, claim, damage, expense or liability (including all reasonable attorneys’ fees and other
expenses reasonably incurred in investigating, preparing or defending against any claim whatsoever) to which they may become subject
under the Act, the Exchange Act or otherwise, arising from information furnished by or on behalf of such Holders, or their successors
or assigns, in writing, for specific inclusion in such registration statement or arising from any omission or the alleged omission
to state a material fact required to be stated therein or necessary to make the statement contained therein not misleading in connection
with the registration of the Registrable Securities, to the same extent and with the same effect as the provisions contained in
Section 5 of the Underwriting Agreement pursuant to which the underwriters have agreed to indemnify the Company.

 

5.3.2 Exercise of Purchase Option.
Nothing contained in this Purchase Option shall be construed as requiring the Holder(s) to exercise their Purchase Option or Warrants
underlying such Purchase Option prior to or after the initial filing of any registration statement or the effectiveness thereof.

 

5.3.3 Documents Delivered to Holders.
The Company shall furnish Chardan, as representative of the Holders participating in any of the foregoing offerings, a signed counterpart,
addressed to the participating Holders, of (i) an opinion of counsel to the Company, dated the effective date of such registration
statement (and, if such registration includes an underwritten public offering, an opinion dated the date of the closing under any
underwriting agreement related thereto), and (ii) a “cold comfort” letter dated the effective date of such registration
statement (and, if such registration includes an underwritten public offering, a letter dated the date of the closing under the
underwriting agreement) signed by the independent public accountants who have issued a report on the Company’s financial
statements included in such registration statement, in each case covering substantially the same matters with respect to such registration
statement (and the prospectus included therein) and, in the case of such accountants’ letter, with respect to events subsequent
to the date of such financial statements, as are customarily covered in opinions of issuer’s counsel and in accountants’
letters delivered to underwriters in underwritten public offerings of securities. The Company shall also deliver promptly to Chardan,
as representative of the Holders participating in the offering, the correspondence and memoranda described below and copies of
all correspondence between the Commission and the Company, its counsel or auditors and all memoranda relating to discussions with
the Commission or its staff with respect to the registration statement and permit Chardan, as representative of the Holders, to
do such investigation, upon reasonable advance notice, with respect to information contained in or omitted from the registration
statement as it deems reasonably necessary to comply with applicable securities laws or rules of FINRA. Such investigation shall
include access to books, records and properties and opportunities to discuss the business of the Company with its officers and
independent auditors, all to such reasonable extent and at such reasonable times and as often as Chardan, as representative of
the Holders, shall reasonably request. The Company shall not be required to disclose any confidential information or other records
to Chardan, as representative of the Holders, or to any other person, until and unless such persons shall have entered into reasonable
confidentiality agreements (in form and substance reasonably satisfactory to the Company), with the Company with respect thereto.

 

    7

     

    

 

5.3.4 Underwriting Agreement. The Company
shall enter into an underwriting agreement with the managing underwriter(s), if any, selected by any Holders whose Registrable
Securities are being registered pursuant to this Section 5, which managing underwriter shall be reasonably acceptable to the Company.
Such agreement shall be reasonably satisfactory in form and substance to the Company, each Holder and such managing underwriters,
and shall contain such representations, warranties and covenants by the Company and such other terms as are customarily contained
in agreements of that type used by the managing underwriter. The Holders shall be parties to any underwriting agreement relating
to an underwritten sale of their Registrable Securities and may, at their option, require that any or all the representations,
warranties and covenants of the Company to or for the benefit of such underwriters shall also be made to and for the benefit of
such Holders. Such Holders shall not be required to make any representations or warranties to or agreements with the Company or
the underwriters except as they may relate to such Holders and their intended methods of distribution. Such Holders, however, shall
agree to such covenants and indemnification and contribution obligations for selling shareholders as are customarily contained
in agreements of that type used by the managing underwriter. Further, such Holders shall execute appropriate custody agreements
and otherwise cooperate fully in the preparation of the registration statement and other documents relating to any offering in
which they include securities pursuant to this Section 5. Each Holder shall also furnish to the Company such information regarding
itself, the Registrable Securities held by it, and the intended method of disposition of such securities as shall be reasonably
required to effect the registration of the Registrable Securities.

 

5.3.5 Rule 144 Sale. Notwithstanding
anything contained in this Section 5 to the contrary, the Company shall have no obligation pursuant to Sections 5.1
or 5.2 to use its best efforts to obtain the registration of Registrable Securities held by any Holder (i) where such Holder
would then be entitled to sell under Rule 144 within any three-month period (or such other period prescribed under Rule 144 as
may be provided by amendment thereof) all of the Registrable Securities then held by such Holder, or (ii) where the number of Registrable
Securities held by such Holder is within the volume limitations under paragraph (e) of Rule 144 (calculated as if such Holder were
an affiliate within the meaning of Rule 144).

 

5.3.6 Supplemental Prospectus. Each
Holder agrees, that upon receipt of any notice from the Company of the happening of any event as a result of which the prospectus
included in the registration statement, as then in effect, includes an untrue statement of a material fact or omits to state a
material fact required to be stated therein or necessary to make the statements therein not misleading in light of the circumstances
then existing, such Holder will immediately discontinue disposition of Registrable Securities pursuant to the registration statement
covering such Registrable Securities until such Holder’s receipt of the copies of a supplemental or amended prospectus, and,
if so desired by the Company, such Holder shall deliver to the Company (at the expense of the Company) or destroy (and deliver
to the Company a certificate of such destruction) all copies, other than permanent file copies then in such Holder’s possession,
of the prospectus covering such Registrable Securities current at the time of receipt of such notice.

 

6.
ADJUSTMENTS.

 

6.1 Adjustments to Exercise Price and
Number of Securities. The Exercise Price and the number of Units underlying the Purchase Option shall be subject to adjustment
from time to time as hereinafter set forth:

 

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6.1.1 Stock Dividends - Split-Ups.
If after the date hereof, and subject to the provisions of Section 6.3 below, the number of outstanding Shares is increased
by a stock dividend payable in Shares or by a split-up of Shares or other similar event, then, on the effective date thereof, the
number of Shares underlying each of the Units purchasable hereunder shall be increased in proportion to such increase in outstanding
shares. In such case, the number of Shares, and the exercise price applicable thereto, underlying the Warrants underlying each
of the Units purchasable hereunder shall be adjusted in accordance with the terms of the Warrants.

 

6.1.2 Aggregation of Shares. If after
the date hereof, and subject to the provisions of Section 6.3, the number of outstanding Shares is decreased by a consolidation,
combination or reclassification of Shares or other similar event, then, on the effective date thereof, the number of Shares underlying
each of the Units purchasable hereunder shall be decreased in proportion to such decrease in outstanding shares and the Exercise
Price shall be proportionately increased. In such case, the number of Shares, and the exercise price applicable thereto, underlying
the Warrants underlying each of the Units purchasable hereunder shall be adjusted in accordance with the terms of the Warrants.

 

6.1.3 Replacement of Securities upon Reorganization,
etc. In case of any reclassification or reorganization of the outstanding Shares other than a change covered by Section
6.1.1 or 6.1.2 hereof or that solely affects the par value of such Shares, or in the case of any merger or consolidation
of the Company with or into another company (other than a consolidation or merger in which the Company is the continuing entity
and that does not result in any reclassification or reorganization of the outstanding Shares), or in the case of any sale or conveyance
to another company or entity of the property of the Company as an entirety or substantially as an entirety in connection with which
the Company is dissolved, the Holder of this Purchase Option shall have the right thereafter (until the expiration of the right
of exercise of this Purchase Option) to receive upon the exercise hereof, for the same aggregate Exercise Price payable hereunder
immediately prior to such event, the kind and amount of shares or other securities or property (including cash) receivable upon
such reclassification, reorganization, merger or consolidation, or upon a dissolution following any such sale or transfer, by a
Holder of the number of Shares of the Company obtainable upon exercise of this Purchase Option and the underlying Warrants immediately
prior to such event; and if any reclassification also results in a change in Shares covered by Section 6.1.1 or 6.1.2,
then such adjustment shall be made pursuant to Sections 6.1.1, 6.1.2 and this Section 6.1.3. The provisions
of this Section 6.1.3 shall similarly apply to successive reclassifications, reorganizations, mergers or consolidations,
sales or other transfers.

 

6.1.4 Changes in Form of Purchase Option.
This form of Purchase Option need not be changed because of any change pursuant to this Section, and a Purchase Option issued after
such change may state the same Exercise Price and the same number of Units as are stated in the Purchase Option as initially issued.
The acceptance by any Holder of the issuance of a new Purchase Option reflecting a required or permissive change shall not be deemed
to waive any rights to an adjustment occurring after the Commencement Date or the computation thereof.

 

6.2 Substitute Purchase Option. In
case of any consolidation of the Company with, or merger of the Company with, or merger of the Company into, another entity (other
than a consolidation or merger which does not result in any reclassification or change of the outstanding Shares), the entity formed
by such consolidation or merger shall execute and deliver to the Holder a supplemental Purchase Option providing that the holder
of each Purchase Option then outstanding or to be outstanding shall have the right thereafter (until the stated expiration of such
Purchase Option) to receive, upon exercise of such Purchase Option, the kind and amount of shares and other securities and property
receivable upon such consolidation or merger, by a holder of the number of Shares of the Company for which such Purchase Option
might have been exercised immediately prior to such consolidation, merger, sale or transfer. Such supplemental Purchase Option
shall provide for adjustments which shall be identical to the adjustments provided in Section 6. The above provision of
this Section shall similarly apply to successive consolidations or mergers.

 

6.3 Elimination of Fractional Interests.
The Company shall not be required to issue certificates representing fractions of Shares or Warrants upon the exercise of the Purchase
Option, nor shall it be required to issue scrip or pay cash in lieu of any fractional interests, it being the intent of the parties
that all fractional interests shall be eliminated by rounding any fraction up to the nearest whole number of Warrants, Rights,
Shares or other securities, properties or rights (or as otherwise provided pursuant to the Warrant Agreement or Rights Agreement,
as the case may be).

 

    9

     

    

 

7. RESERVATION AND
LISTING. The Company shall at all times reserve and keep available out of its authorized but unissued Shares, solely
for the purpose of issuance upon exercise of the Purchase Option or the Warrants or Rights underlying the Purchase Option, such
number of Shares or other securities, properties or rights as shall be issuable upon the exercise thereof. The Company covenants
and agrees that, upon exercise of the Purchase Option and payment of the Exercise Price therefor, all Shares and other securities
issuable upon such exercise shall be duly and validly issued, fully paid and non-assessable and not subject to preemptive rights
of any shareholder. The Company further covenants and agrees that upon conversion of the Rights or exercise of the Warrants underlying
the Purchase Option and payment of the respective Warrant exercise price therefor, all Shares and other securities issuable upon
such exercise shall be duly and validly issued, fully paid and non-assessable and not subject to preemptive rights of any shareholders.
As long as the Purchase Option shall be outstanding, the Company shall use its best efforts to cause all (i) Units and Shares issuable
upon exercise of the Purchase Option, (ii) Warrants issuable upon exercise of the Purchase Option (iii) Shares issuable upon exercise
of the Warrants included in the Units issuable upon exercise of the Purchase Option, (iv) Rights issuable upon exercise of the
Purchase Option and (v) Shares underlying the Rights included in the Units issuable upon exercise of the Purchase Option to be
listed and/or quoted (subject to official notice of issuance) on all securities exchanges (or, if applicable, on the OTC Bulletin
Board or OTC Markets Group, Inc. or any successor trading market) on which the Units, Shares, Rights or Warrants may then be listed
and/or quoted.

 

8.
CERTAIN NOTICE REQUIREMENTS.

 

8.1 Holder’s Right to Receive Notice.
Nothing herein shall be construed as conferring upon the Holders the right to vote or consent as a shareholders for the election
of directors or any other matter, or as having any rights whatsoever as a shareholders of the Company. If, however, at any time
prior to the expiration of the Purchase Option and its exercise, any of the events described in Section 8.2 shall occur,
then, in each such event, the Company shall give written notice of such event at least fifteen days prior to the date fixed as
a record date or the date of closing the transfer books for the determination of the shareholders entitled to such dividend, distribution,
conversion or exchange of securities or subscription rights, or entitled to vote on such proposed dissolution, liquidation, winding
up or sale. Such notice shall specify such record date or the date of the closing of the transfer books, as the case may be. Notwithstanding
the foregoing, the Company shall deliver to each Holder a copy of each notice given to the other shareholders of the Company at
the same time and in the same manner that such notice is given to the shareholders.

 

8.2 Events Requiring Notice. The
Company shall be required to give the notice described in this Section 8 upon one or more of the following events: (i) if the Company
shall take a record of the holders of its Shares for the purpose of entitling them to receive a dividend or distribution payable
otherwise than in cash, or a cash dividend or distribution payable otherwise than out of retained earnings, as indicated by the
accounting treatment of such dividend or distribution on the books of the Company, or (ii) the Company shall offer to all the holders
of its Shares any additional shares of capital stock of the Company or securities convertible into or exchangeable for shares of
capital stock of the Company, or any option, right or warrant to subscribe therefor, or (iii) a dissolution, liquidation or winding
up of the Company (other than in connection with a consolidation or merger) or a sale of all or substantially all of its property,
assets and business shall be proposed.

 

8.3 Notice of Change in Exercise Price.
The Company shall, promptly after an event requiring a change in the Exercise Price pursuant to Section 6 hereof, send notice to
the Holders of such event and change (“Price Notice”). The Price Notice shall describe the event causing
the change and the method of calculating same and shall be certified as being true and accurate by the Company’s Chief Executive
Officer.

 

8.4 Transmittal of Notices. All notices,
requests, consents and other communications under this Purchase Option shall be in writing and shall be deemed to have been duly
made when hand delivered, or mailed by express mail or private courier service: (i) if to the registered Holder of the Purchase
Option, to the address of such Holder as shown on the books of the Company, or (ii) if to the Company, to the following address
or to such other address as the Company may designate by notice to the Holders:

 

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Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

Attn: Wei Chen

Telephone: (631) 220-3541

 

9.
MISCELLANEOUS.

 

9.1 Amendment The Company and Chardan
may from time to time supplement or amend this Purchase Option without the approval of any of the Holders in order to cure any
ambiguity, to correct or supplement any provision contained herein that may be defective or inconsistent with any other provisions
herein, or to make any other provisions in regard to matters or questions arising hereunder that the Company and Chardan may deem
necessary or desirable and that the Company and Chardan deem shall not adversely affect the interest of the Holders. All other
modifications or amendments shall require the written consent of and be signed by the party against whom enforcement of the modification
or amendment is sought.

 

9.2 Headings. The headings contained
herein are for the sole purpose of convenience of reference, and shall not in any way limit or affect the meaning or interpretation
of any of the terms or provisions of this Purchase Option.

 

9.3 Entire Agreement. This Purchase
Option (together with the other agreements and documents being delivered pursuant to or in connection with this Purchase Option)
constitutes the entire agreement of the parties hereto with respect to the subject matter hereof, and supersedes all prior agreements
and understandings of the parties, oral and written, with respect to the subject matter hereof.

 

9.4 Binding Effect. This Purchase
Option shall inure solely to the benefit of and shall be binding upon the Holder and the Company and their permitted assignees,
respective successors, legal representative and assigns, and no other person shall have or be construed to have any legal or equitable
right, remedy or claim under or in respect of or by virtue of this Purchase Option or any provisions herein contained.

 

9.5 Governing Law; Submission to Jurisdiction.
This Purchase Option shall be governed by and construed and enforced in accordance with the laws of the State of New York, without
giving effect to conflict of laws principles thereof. Each of the Holder and the Company hereby agrees that any action, proceeding
or claim against it arising out of, or relating in any way to this Purchase Option shall be brought and enforced in the New York
Supreme Court, County of New York, or in the United States District Court for the Southern District of New York, and irrevocably
submits to such jurisdiction, which jurisdiction shall be exclusive. Each of the Holder and the Company hereby waives any objection
to such exclusive jurisdiction and that such courts represent an inconvenient forum. Any process or summons to be served upon the
Company may be served by transmitting a copy thereof by registered or certified mail, return receipt requested, postage prepaid,
addressed to it at the address set forth in Section 8.4 hereof. Such mailing shall be deemed personal service and shall
be legal and binding upon the Company in any action, proceeding or claim. The Company and the Holder agree that the prevailing
party(ies) in any such action shall be entitled to recover from the other party(ies) all of its reasonable attorneys’ fees
and expenses relating to such action or proceeding and/or incurred in connection with the preparation therefore.

 

9.6 Waiver, Etc. The failure of the
Company or the Holder to at any time enforce any of the provisions of this Purchase Option shall not be deemed or construed to
be a waiver of any such provision, nor to in any way affect the validity of this Purchase Option or any provision hereof or the
right of the Company or any Holder to thereafter enforce each and every provision of this Purchase Option. No waiver of any breach,
non-compliance or non-fulfillment of any of the provisions of this Purchase Option shall be effective unless set forth in a written
instrument executed by the party or parties against whom or which enforcement of such waiver is sought; and no waiver of any such
breach, non-compliance or non- fulfillment shall be construed or deemed to be a waiver of any other or subsequent breach or non-compliance.

 

9.7 Execution in Counterparts. This
Purchase Option may be executed in one or more counterparts, and by the different parties hereto in separate counterparts, each
of which shall be deemed to be an original, but all of which taken together shall constitute one and the same agreement, and shall
become effective when one or more counterparts has been signed by each of the parties hereto and delivered to each of the other
parties hereto.

 

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9.8 Exchange Agreement. As a condition
of the Holder’s receipt and acceptance of this Purchase Option, Holder agrees that, at any time prior to the complete exercise
of this Purchase Option by Holder, if the Company and Chardan enter into an agreement (“Exchange Agreement”)
pursuant to which they agree that all outstanding Purchase Options will be exchanged for securities or cash or a combination of
both, then Holder shall agree to such exchange and become a party to the Exchange Agreement.

 

[Signature Page Follows]

 

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IN WITNESS WHEREOF, the Company has caused this Purchase Option
to be signed by its duly authorized officer as of the 6th day of August, 2019.

 

	 	ORISUN ACQUISITION CORP.
	 	 
	 	By:	/s/
    Wei Chen
	 	 	Name: Wei Chen
	 	 	Title: Chief Executive Officer

 

     

     

    

 

Form to be used to exercise Purchase Option

 

Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

 

Date:_________________, 20___

 

The undersigned hereby elects irrevocably
to exercise all or a portion of the within Purchase Option and to purchase ____ Units of Orisun Acquisition Corp. and hereby makes
payment of $____________ (at the rate of $_________ per Unit) in payment of the Exercise Price pursuant thereto. Please issue the
securities as to which this Purchase Option is exercised in accordance with the instructions given below.

 

or

 

The undersigned hereby elects irrevocably
to convert its right to purchase _________ Units purchasable under the within Purchase Option by surrender of the unexercised portion
of the attached Purchase Option (with a “Value” based of $_______ based on a “Market Price” of $_______).
Please issue the securities comprising the Units as to which this Purchase Option is exercised in accordance with the instructions
given below.

 

NOTICE: The signature to this assignment
must correspond with the name as written upon the face of the purchase option 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).

 

INSTRUCTIONS FOR REGISTRATION OF SECURITIES

 

Name

	 
	(Print in Block Letters)
	
         

        Address

         

 

     

     

    

 

Form to be used to assign Purchase Option:

 

ASSIGNMENT

 

(To be executed by the registered Holder
to effect a transfer of the within Purchase Option):

 

FOR VALUE RECEIVED,______________________________________________
does hereby sell, assign and transfer unto___________________________________________ the right to purchase __________ Units of
Orisun Acquisition Corp.. (“Company”) evidenced by the within Purchase Option and does hereby authorize
the Company to transfer such right on the books of the Company.

 

Dated:___________________, 20___

 

	 	 
	 	Signature

 

	 	 	 
	 	NOTICE: The signature to this assignment must correspond with the name as written upon the face of the purchase option 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).Exhibit 10.1

 

August 2, 2019

 

Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

 

Chardan Capital Markets,
LLC

17 State Street, Suite 1600

New York, NY 10004

 

		Re:	Initial Public Offering

 

Ladies and Gentlemen:

 

This letter is
being delivered to you in accordance with the Underwriting Agreement (the “Underwriting Agreement”) entered
into by and between Orisun Acquisition Corp., a Delaware corporation (the “Company”), and Chardan Capital
Markets, LLC, as Representative (the “Representative”) of the several underwriters named on Schedule
A thereto (the “Underwriters”), relating to an underwritten initial public offering (the “IPO”)
of the Company’s units (the “Units”), each comprised of one share of common stock of the Company,
par value $0.00001 per share (the “Common Stock”), one redeemable warrant, each warrant entitling its
holder to purchase one-half (1/2) of a share of Common Stock at an exercise price of $11.50 per full share (the “Warrants”),
and one right to receive one-tenth (1/10) of a share of Common Stock (the “Rights”). Certain capitalized
terms used herein are defined in paragraph 14 hereof.

 

In order to induce the
Company and the Underwriters to enter into the Underwriting Agreement and to proceed with the IPO, and in recognition of the benefit
that such IPO will confer upon the undersigned, and for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the undersigned hereby agrees with the Company as follows:

 

1. If the Company solicits
approval of its stockholders of a Business Combination, the undersigned will vote all shares of Common Stock beneficially owned
by him, her or it, whether acquired before, in or after the IPO, in favor of such Business Combination.

 

2. (a) Unless the Company’s
stockholders are previously given the option to redeem their shares in connection with amending applicable documents to extend
the time that the Company has to complete a Business Combination and that the Company fails to consummate a Business Combination
within 12 months from the closing of the Company’s IPO (or, in the event that the Company extended the period of time to
consummate a business combination up to three times, each by an additional three months, within 21 months) from the closing of
the Company’s IPO, the undersigned shall take all reasonable steps to (i) cause the Trust Fund to be liquidated and distributed
to the holders of the IPO Shares and (ii) cause the Company to liquidate as soon as reasonably practicable.

 

     

     

    

 

(b) The undersigned
hereby waives any and all right, title, interest or claim of any kind in or to any distribution of the Trust Fund and any remaining
net assets of the Company as a result of such liquidation with respect to his, her or its Insider Shares including any shares underlying
the Private Units (“Claim”) and hereby waives any Claim the undersigned may have in the future as a result
of, or arising out of, any contracts or agreements with the Company and will not seek recourse against the Trust Fund for any reason
whatsoever. The undersigned acknowledges and agrees that there will be no distribution from the Trust Fund with respect to any
Warrants or Rights and with respect to all securities underlying the Private Units, all of which will terminate on the Company’s
liquidation.

 

[(c) Intentionally
Omitted.]

 

[(d) Intentionally
Omitted.]

 

3. [Intentionally Omitted.]

 

4. The undersigned will
escrow all of his, her or its Insider Shares pursuant to the terms of a Stock Escrow Agreement, which the Company will enter into
with the undersigned and an escrow agent acceptable to the Company.

 

5. The undersigned agrees
that until the Company consummates a Business Combination, the undersigned’s Private Units will be subject to the transfer
restrictions described in the Subscription Agreement relating to the undersigned’s Private Units.

 

6. In order to minimize
potential conflicts of interest which may arise from multiple affiliations, the undersigned agrees to present to the Company for
its consideration, prior to presentation to any other person or entity, any suitable opportunity to acquire a target business,
until the earlier of the consummation by the Company of a Business Combination or the liquidation of the Company, subject to any
pre-existing fiduciary and contractual obligations the undersigned might have.

 

7. (a) The undersigned
acknowledges and agrees that prior to entering into a Business Combination with a target business that is affiliated with any Insiders
of the Company or their affiliates, including any company that is a portfolio company of, or otherwise affiliated with, or has
received financial investment from, an entity with which any Insider or their affiliates is affiliated, such transaction must be
approved by a majority of the Company’s disinterested independent directors and the Company must obtain an opinion from an
independent investment banking firm that such Business Combination is fair to the Company’s unaffiliated stockholders from
a financial point of view.

 

(b) The undersigned
hereby agrees and acknowledges that (i) each of the Underwriters and the Company may be irreparably injured in the event of a breach
of any of the obligations contained in this letter, (ii) monetary damages may not be an adequate remedy for such breach and (iii)
the non-breaching party shall be entitled to injunctive relief, in addition to any other remedy that such party may have in law
or in equity, in the event of such breach.

 

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8. Neither the undersigned,
any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to receive and will not accept
any compensation or other cash payment prior to, or for services rendered in connection with, the consummation of the Business
Combination; provided that the Company shall be allowed to repay working capital loans made by the undersigned to the Company
in cash upon consummation of the Business Combination. Notwithstanding the foregoing, the undersigned and any affiliate of the
undersigned shall be entitled to reimbursement from the Company for their out-of-pocket expenses incurred in connection with identifying,
investigating and consummating a Business Combination.

 

9. Neither the undersigned,
any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to receive or accept a finder’s
fee or any other compensation in the event the undersigned, any member of the family of the undersigned or any affiliate of the
undersigned originates a Business Combination.

 

10. The undersigned’s
FINRA Questionnaire previously furnished to the Company and the Representative is true and accurate in all material respects. The
undersigned represents and warrants that:

 

		(a)	He, she or it has never had a petition under the federal bankruptcy laws or any state insolvency law been filed by or against
(i) him, her or it, or any partnership in which he or she was a general partner at or within two years before the time of filing;
or (ii) any corporation or business association of which he or she was an executive officer at or within two years before the time
of such filing;

 

		(b)	He, she or it has never had a receiver, fiscal agent or similar officer been appointed by a court for his business or property,
or any such partnership;

 

		(c)	He, she or it has never been convicted of fraud in a civil or criminal proceeding;

 

		(d)	He, she or it has never been convicted in a criminal proceeding or named the subject of a pending criminal proceeding (excluding
traffic violations and minor offenses);

 

		(e)	He, she or it has never been the subject of any order, judgment or decree, not subsequently reversed, suspended or vacated,
of any court of competent jurisdiction, permanently or temporarily enjoining or otherwise limiting him, her or it from (i) acting
as a futures commission merchant, introducing broker, commodity trading advisor, commodity pool operator, floor broker, leverage
transaction merchant, any other person regulated by the Commodity Futures Trading Commission (“CFTC”) or an associated
person of any of the foregoing, or as an investment adviser, underwriter, broker or dealer in securities, or as an affiliated person,
director or employee of any investment company, bank, savings and loan association or insurance company, or from engaging in or
continuing any conduct or practice in connection with any such activity; or (ii) engaging in any type of business practice;
or (iii) engaging in any activity in connection with the purchase or sale of any security or commodity or in connection with
any violation of federal or state securities or federal commodities laws;

 

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		(f)	He, she, or it has never been the subject of any order, judgment or decree, not subsequently reversed, suspended or vacated,
of any federal or state authority barring, suspending or otherwise limiting for more than 60 days his, her or its right to engage
in any activity described in 10(e)(i) above, or to be associated with persons engaged in any such activity;

 

		(g)	He, she, or it has never been found by a court of competent jurisdiction in a civil action or by the SEC to have violated any
federal or state securities law, where the judgment in such civil action or finding by the SEC has not been subsequently reversed,
suspended or vacated;

 

		(h)	He, she, or it has never been found by a court of competent jurisdiction in a civil action or by the CFTC to have violated
any federal commodities law, where the judgment in such civil action or finding by the CFTC has not been subsequently reversed,
suspended or vacated;

 

		(i)	He, she, or it has never been the subject of, or a party to, any Federal, State or foreign judicial or administrative order,
judgment, decree or finding, not subsequently reversed, suspended or vacated, relating to an alleged violation of (i) any Federal,
State or foreign securities or commodities law or regulation, (ii) any law or regulation respecting financial institutions or insurance
companies including, but not limited to, a temporary or permanent injunction, order of disgorgement or restitution, civil money
penalty or temporary or permanent cease-and desist order, or removal or prohibition order or (iii) any law or regulation prohibiting
mail or wire fraud or fraud in connection with any business entity;

 

		(j)	He, she or it has never been the subject of, or party to, any sanction or order, not subsequently reversed, suspended or vacated,
or any self-regulatory organization, any registered entity, or any equivalent exchange, association, entity or organization that
has disciplinary authority over its members or persons associated with a member;

 

		(k)	He, she or it has never been convicted of any felony or misdemeanor: (i) in connection with the purchase or sale of any security;
(ii) involving the making of any false filing with the SEC; or (iii) arising out of the conduct of the business of an underwriter,
broker, dealer, municipal securities dealer, investment advisor or paid solicitor of purchasers of securities;

 

    4

     

    

 

		(l)	He, she or it was never subject to a final order of a state or foreign securities commission (or an agency of officer of a
state performing like functions); a state or foreign authority that supervises or examines banks, savings associations, or credit
unions; a state or foreign insurance commission (or an agency or officer of a state performing like functions); an appropriate
federal or foreign banking agency; the CFTC; or the National Credit Union Administration that is based on a violation of any law
or regulation that prohibits fraudulent, manipulative, or deceptive conduct;

 

		(m)	He, she or it has never been subject to any order, judgment or decree of any court of competent jurisdiction, that, at the
time of the sale of the Units, restrained or enjoined him, her or it from engaging or continuing to engage in any conduct or practice:
(i) in connection with the purchase or sale of any security; (ii) involving the making of any false filing with the SEC or any
foreign regulatory agency with similar functions; or (iii) arising out of the conduct of the business of an underwriter, broker,
dealer, municipal securities dealer, investment adviser or paid solicitor of purchasers of securities;

 

		(n)	He, she or it has never been subject to any order of the SEC or any foreign regulatory agency with similar functions that orders
him, her or it to cease and desist from committing or causing a future violation of: (i) any scienter-based anti-fraud provision
of the federal securities laws, including, but not limited to, Section 17(a)(1) of the Securities Act, Section 10(b) of the Exchange
Act and Rule 10b-5 thereunder, Section 15(c) and Section 206(1) of the Advisers Act or any other rule or regulation thereunder;
or (ii) Section 5 of the Securities Act;

 

		(o)	He, she or it has never filed (as a registrant or issuer), or been named as an underwriter in any registration statement or
Regulation A offering statement filed with the SEC that was the subject of a refusal order, stop order, or order suspending the
Regulation A exemption, or is, currently, the subject of an investigation or proceeding to determine whether a stop order or suspension
order should be issued;

 

		(p)	He, she or it has never been subject to a United States Postal Service false representation order, or is currently subject
to a temporary restraining order or preliminary injunction with respect to conduct alleged by the United States Postal Service
to constitute a scheme or device for obtaining money or property through the mail by means of false representations;

 

		(q)	He, she or it is not subject to a final order of a state securities commission (or an agency of officer of a state performing
like functions); a state authority that supervises or examines banks, savings associations, or credit unions; a state insurance
commission (or an agency or officer of a state performing like functions); an appropriate federal banking agency; the CFTC; or
the National Credit Union Administration that bars the undersigned from: (i) association with an entity regulated by such commission,
authority, agency or officer; (ii) engaging in the business of securities, insurance or banking; or (iii) engaging in savings association
or credit union activities;

 

    5

     

    

 

		(r)	He, she or it is not subject to an order of the SEC entered pursuant to section 15(b) or 15B(c) of the Securities Exchange
Act of 1934 (the “Exchange Act”) or section 203(e) or 203(f) of the Investment Advisers Act of 1940 (the “Advisers
Act”) that: (i) suspends or revokes the undersigned’s registration as a broker, dealer, municipal securities dealer
or investment adviser; (ii) places limitations on the activities, functions or operations of, or imposes civil money penalties
on, such person; or (iii) bars the undersigned from being associated with any entity or from participating in the offering of any
penny stock; and

 

		(s)	He, she or it has never been suspended or expelled from membership in, or suspended or barred from association with a member
of, a securities self-regulatory organization (e.g., a registered national securities exchange or a registered national or affiliated
securities association) for any act or omission to act constituting conduct inconsistent with just and equitable principles of
trade.

 

11. [Intentionally Omitted.]

 

12. The undersigned hereby
waives his, her or its right to exercise redemption rights with respect to any shares of Common Stock owned or to be owned by the
undersigned, directly or indirectly (or to sell such shares to the Company in a tender offer), whether purchased by the undersigned
prior to the IPO, in the IPO or in the aftermarket, and agrees that he, she or it will not seek redemption with respect to or otherwise
sell, such shares in connection with any vote to approve a Business Combination with respect thereto, a vote to amend the provisions
of the Company’s Amended and Restated Certificate of Incorporation, or a tender offer by the Company prior to a Business
Combination.

 

13. The undersigned hereby
agrees to not propose, or vote in favor of, an amendment to the Company’s Amended and Restated Certificate of Incorporation
with respect to the Company’s pre-Business Combination activities prior to the consummation of a Business Combination unless
the Company offers holders of IPO Shares the right to receive their pro rata portion of the funds then held in the Trust Fund.

 

14. In connection with
Section 5-1401 of the General Obligations Law of the State of New York, this letter agreement shall be governed by, and construed
in accordance with, the laws of the State of New York without regard to principles of conflicts of law that would result in the
application of the substantive law of another jurisdiction. The parties hereto agree that any action, proceeding or claim arising
out of or relating in any way to this letter agreement shall be resolved through final and binding arbitration in accordance with
the International Arbitration Rules of the American Arbitration Association (“AAA”). The arbitration shall be brought
before the AAA International Center for Dispute Resolution’s offices in New York City, New York, will be conducted in English
and will be decided by a panel of three arbitrators selected from the AAA Commercial Disputes Panel and that the arbitrator panel’s
decision shall be final and enforceable by any court having jurisdiction over the party from whom enforcement is sought. The cost
of such arbitrators and arbitration services, together with the prevailing party’s legal fees and expenses, shall be borne
by the non-prevailing party or as otherwise directed by the arbitrators.

 

    6

     

    

 

15. As used herein, (i)
a “Business Combination” shall mean a merger, share exchange, asset acquisition, contractual arrangement,
share purchase, recapitalization, reorganization or other similar business combination with one or more businesses or entities;
(ii) “Insiders” shall mean all officers, directors and stockholders of the Company immediately prior
to the IPO; (iii) “Insider Shares” shall mean all of the shares of Common Stock of the Company acquired
by an Insider prior to the IPO and any shares of Common Stock underlying the Private Units; (iv) “IPO Shares”
shall mean the shares of Common Stock issued in the Company’s IPO; (v) “Private Units” shall mean
(x) the Units purchased in the private placement taking place simultaneously with the consummation of the Company’s IPO and
(y) the additional Units that may be purchased in connection with the exercise of the over-allotment option by the underwriters
in the IPO as described in the Registration Statement; (vi) “Registration Statement” means the registration
statement on Form S-1 filed by the Company with respect to the IPO; and (vii) “Trust Fund” shall mean
the trust fund into which a portion of the net proceeds of the Company’s IPO will be deposited.

 

16. Any notice, consent
or request to be given in connection with any of the terms or provisions of this letter agreement shall be in writing and shall
be sent by express mail or similar private courier service, by certified mail (return receipt requested), by hand delivery or facsimile
transmission.

 

If to the Representative:

 

Chardan Capital Markets, LLC

17 State Street, Suite 1600

New York, NY 10004

Attn: George Kaufman

Facsimile: (646) 465-9039

 

with a copy (which copy shall not constitute
notice) to:

 

Ellenoff Grossman & Schole LLP 

1345 Avenue of the Americas

New York, New York 10105

Attn: Stuart Neuhauser, Esq. and Ari Edelman, Esq.

Facsimile.: (212) 370-7889

 

If to the Company:

 

Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

Attn: Wei Chen, Chief Executive Officer

 

    7

     

    

 

with a copy (which copy shall not constitute
notice) to:

 

Loeb & Loeb LLP

345 Park Avenue

New York, NY 10154

Attn: Giovanni Caruso, Esq.

Facsimile: (212) 504-3013

 

17. No party hereto may
assign either this letter agreement or any of its rights, interests, or obligations hereunder without the prior written consent
of the other party. Any purported assignment in violation of this paragraph shall be void and ineffectual and shall not operate
to transfer or assign any interest or title to the purported assignee. This letter agreement shall be binding on the parties hereto
and any successors and assigns thereof.

 

18. This Letter Agreement
constitutes the entire agreement and understanding of the parties hereto in respect of the subject matter hereof and supersedes
all prior understandings, agreements, or representations by or among the parties hereto, written or oral, to the extent they relate
in any way to the subject matter hereof or the transactions contemplated hereby. This Letter Agreement may not be changed, amended,
modified or waived (other than to correct a typographical error) as to any particular provision, except by a written instrument
executed by all parties hereto.

 

19. The undersigned acknowledges
and understands that the Underwriters and the Company will rely upon the agreements, representations and warranties set forth herein
in proceeding with the IPO. Nothing contained herein shall be deemed to render the Underwriters a representative of, or a fiduciary
with respect to, the Company, its stockholders or any creditor or vendor of the Company with respect to the subject matter hereof.

 

    8

     

    

 

	 	Everstone Investments LLC
	 	 	 
	 	By:	/s/
    Wei Chen
	 	Name:  	Wei Chen
	 	Title: 	Managing Member

 

 

 

 

 

Signature Page to Insider Letter

 

    9

     

    

 

August
2, 2019

 

Orisun
Acquisition Corp.

555
Madison Avenue, Room 543

New
York, NY 10022

 

Chardan
Capital Markets, LLC

17
State Street, Suite 1600

New
York, NY 10004

 

		Re:	Initial
                                         Public Offering

 

Ladies
and Gentlemen:

 

This
letter is being delivered to you in accordance with the Underwriting Agreement (the “Underwriting Agreement”)
entered into by and between Orisun Acquisition Corp., a Delaware corporation (the “Company”), and Chardan
Capital Markets, LLC, as Representative (the “Representative”) of the several underwriters named on
Schedule A thereto (the “Underwriters”), relating to an underwritten initial public offering (the “IPO”)
of the Company’s units (the “Units”), each comprised of one share of common stock of the Company,
par value $0.00001 per share (the “Common Stock”), one redeemable warrant, each warrant entitling its
holder to purchase one-half (1/2) of a share of Common Stock at an exercise price of $11.50 per full share (the “Warrants”),
and one right to receive one-tenth (1/10) of a share of Common Stock (the “Rights”). Certain capitalized
terms used herein are defined in paragraph 14 hereof.

 

In
order to induce the Company and the Underwriters to enter into the Underwriting Agreement and to proceed with the IPO, and in
recognition of the benefit that such IPO will confer upon the undersigned, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the undersigned hereby agrees with the Company as follows:

 

1.
If the Company solicits approval of its stockholders of a Business Combination, the undersigned will vote all shares of Common
Stock beneficially owned by him, her or it, whether acquired before, in or after the IPO, in favor of such Business Combination.

 

2.
(a) Unless the Company’s stockholders are previously given the option to redeem their shares in connection with amending
applicable documents to extend the time that the Company has to complete a Business Combination and that the Company fails to
consummate a Business Combination within 12 months from the closing of the Company’s IPO (or, in the event that the Company
extended the period of time to consummate a business combination up to three times, each by an additional three months, within
21 months) from the closing of the Company’s IPO, the undersigned shall take all reasonable steps to (i) cause the Trust
Fund to be liquidated and distributed to the holders of the IPO Shares and (ii) cause the Company to liquidate as soon as reasonably
practicable.

 

    10

     

    

 

(b)
The undersigned hereby waives any and all right, title, interest or claim of any kind in or to any distribution of the Trust Fund
and any remaining net assets of the Company as a result of such liquidation with respect to his, her or its Insider Shares (“Claim”)
and hereby waives any Claim the undersigned may have in the future as a result of, or arising out of, any contracts or agreements
with the Company and will not seek recourse against the Trust Fund for any reason whatsoever.

 

[(c)
Intentionally Omitted.]

 

[(d)
Intentionally Omitted.]

 

3.
[Intentionally Omitted.]

 

4.
The undersigned will escrow all of his, her or its Insider Shares pursuant to the terms of a Stock Escrow Agreement, which the
Company will enter into with the undersigned and an escrow agent acceptable to the Company.

 

5.
[Intentionally Omitted.]

 

6.
In order to minimize potential conflicts of interest which may arise from multiple affiliations, the undersigned agrees to present
to the Company for its consideration, prior to presentation to any other person or entity, any suitable opportunity to acquire
a target business, until the earlier of the consummation by the Company of a Business Combination or the liquidation of the Company,
subject to any pre-existing fiduciary and contractual obligations the undersigned might have.

 

7.
(a) The undersigned acknowledges and agrees that prior to entering into a Business Combination with a target business that is
affiliated with any Insiders of the Company or their affiliates, including any company that is a portfolio company of, or otherwise
affiliated with, or has received financial investment from, an entity with which any Insider or their affiliates is affiliated,
such transaction must be approved by a majority of the Company’s disinterested independent directors and the Company must
obtain an opinion from an independent investment banking firm that such Business Combination is fair to the Company’s unaffiliated
stockholders from a financial point of view.

 

(b)
The undersigned hereby agrees and acknowledges that (i) each of the Underwriters and the Company may be irreparably injured in
the event of a breach of any of the obligations contained in this letter, (ii) monetary damages may not be an adequate remedy
for such breach and (iii) the non-breaching party shall be entitled to injunctive relief, in addition to any other remedy that
such party may have in law or in equity, in the event of such breach.

 

8.
Neither the undersigned, any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to
receive and will not accept any compensation or other cash payment prior to, or for services rendered in connection with, the
consummation of the Business Combination; provided that the Company shall be allowed to repay working capital loans made
by the undersigned to the Company in cash upon consummation of the Business Combination. Notwithstanding the foregoing, the undersigned
and any affiliate of the undersigned shall be entitled to reimbursement from the Company for their out-of-pocket expenses incurred
in connection with identifying, investigating and consummating a Business Combination.

 

    11

     

    

 

9.
Neither the undersigned, any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to
receive or accept a finder’s fee or any other compensation in the event the undersigned, any member of the family of the
undersigned or any affiliate of the undersigned originates a Business Combination.

 

10.
The undersigned agrees to be a director/officer of the Company until the earlier of the consummation by the Company of a Business
Combination or the liquidation of the Company. The undersigned’s biographical information previously furnished to the Company
and the Representative is true and accurate in all material respects, does not omit any material information with respect to the
undersigned’s biography and contains all of the information required to be disclosed pursuant to Item 401 of Regulation
S-K, promulgated under the Securities Act of 1933. The undersigned’s FINRA Questionnaire previously furnished to the Company
and the Representative is true and accurate in all material respects. The undersigned represents and warrants that:

 

		(a)	He,
                                         she or it has never had a petition under the federal bankruptcy laws or any state insolvency
                                         law been filed by or against (i) him, her or it, or any partnership in which he or she
                                         was a general partner at or within two years before the time of filing; or (ii) any corporation
                                         or business association of which he or she was an executive officer at or within two
                                         years before the time of such filing;

 

		(b)	He,
                                         she or it has never had a receiver, fiscal agent or similar officer been appointed by
                                         a court for his business or property, or any such partnership;

 

		(c)	He,
                                         she or it has never been convicted of fraud in a civil or criminal proceeding;

 

		(d)	He,
                                         she or it has never been convicted in a criminal proceeding or named the subject of a
                                         pending criminal proceeding (excluding traffic violations and minor offenses);

 

		(e)	He,
                                         she or it has never been the subject of any order, judgment or decree, not subsequently
                                         reversed, suspended or vacated, of any court of competent jurisdiction, permanently or
                                         temporarily enjoining or otherwise limiting him, her or it from (i) acting as a futures
                                         commission merchant, introducing broker, commodity trading advisor, commodity pool operator,
                                         floor broker, leverage transaction merchant, any other person regulated by the Commodity
                                         Futures Trading Commission (“CFTC”) or an associated person of any of the
                                         foregoing, or as an investment adviser, underwriter, broker or dealer in securities,
                                         or as an affiliated person, director or employee of any investment company, bank, savings
                                         and loan association or insurance company, or from engaging in or continuing any conduct
                                         or practice in connection with any such activity; or (ii) engaging in any type of
                                         business practice; or (iii) engaging in any activity in connection with the purchase
                                         or sale of any security or commodity or in connection with any violation of federal or
                                         state securities or federal commodities laws;

 

    12

     

    

 

		(f)	He,
                                         she, or it has never been the subject of any order, judgment or decree, not subsequently
                                         reversed, suspended or vacated, of any federal or state authority barring, suspending
                                         or otherwise limiting for more than 60 days his, her or its right to engage in any activity
                                         described in 10(e)(i) above, or to be associated with persons engaged in any such activity;

 

		(g)	He,
                                         she, or it has never been found by a court of competent jurisdiction in a civil action
                                         or by the SEC to have violated any federal or state securities law, where the judgment
                                         in such civil action or finding by the SEC has not been subsequently reversed, suspended
                                         or vacated;

 

		(h)	He,
                                         she, or it has never been found by a court of competent jurisdiction in a civil action
                                         or by the CFTC to have violated any federal commodities law, where the judgment in such
                                         civil action or finding by the CFTC has not been subsequently reversed, suspended or
                                         vacated;

 

		(i)	He,
                                         she, or it has never been the subject of, or a party to, any Federal, State or foreign
                                         judicial or administrative order, judgment, decree or finding, not subsequently reversed,
                                         suspended or vacated, relating to an alleged violation of (i) any Federal, State or foreign
                                         securities or commodities law or regulation, (ii) any law or regulation respecting financial
                                         institutions or insurance companies including, but not limited to, a temporary or permanent
                                         injunction, order of disgorgement or restitution, civil money penalty or temporary or
                                         permanent cease-and desist order, or removal or prohibition order or (iii) any law or
                                         regulation prohibiting mail or wire fraud or fraud in connection with any business entity;

 

		(j)	He,
                                         she or it has never been the subject of, or party to, any sanction or order, not subsequently
                                         reversed, suspended or vacated, or any self-regulatory organization, any registered entity,
                                         or any equivalent exchange, association, entity or organization that has disciplinary
                                         authority over its members or persons associated with a member;

 

		(k)	He,
                                         she or it has never been convicted of any felony or misdemeanor: (i) in connection with
                                         the purchase or sale of any security; (ii) involving the making of any false filing with
                                         the SEC; or (iii) arising out of the conduct of the business of an underwriter, broker,
                                         dealer, municipal securities dealer, investment advisor or paid solicitor of purchasers
                                         of securities;

 

		(l)	He,
                                         she or it was never subject to a final order of a state or foreign securities commission
                                         (or an agency of officer of a state performing like functions); a state or foreign authority
                                         that supervises or examines banks, savings associations, or credit unions; a state or
                                         foreign insurance commission (or an agency or officer of a state performing like functions);
                                         an appropriate federal or foreign banking agency; the CFTC; or the National Credit Union
                                         Administration that is based on a violation of any law or regulation that prohibits fraudulent,
                                         manipulative, or deceptive conduct;

 

    13

     

    

 

		(m)	He,
                                         she or it has never been subject to any order, judgment or decree of any court of competent
                                         jurisdiction, that, at the time of the sale of the Units, restrained or enjoined him,
                                         her or it from engaging or continuing to engage in any conduct or practice: (i) in connection
                                         with the purchase or sale of any security; (ii) involving the making of any false filing
                                         with the SEC or any foreign regulatory agency with similar functions; or (iii) arising
                                         out of the conduct of the business of an underwriter, broker, dealer, municipal securities
                                         dealer, investment adviser or paid solicitor of purchasers of securities;

 

		(n)	He,
                                         she or it has never been subject to any order of the SEC or any foreign regulatory agency
                                         with similar functions that orders him, her or it to cease and desist from committing
                                         or causing a future violation of: (i) any scienter-based anti-fraud provision of the
                                         federal securities laws, including, but not limited to, Section 17(a)(1) of the Securities
                                         Act, Section 10(b) of the Exchange Act and Rule 10b-5 thereunder, Section 15(c) and Section
                                         206(1) of the Advisers Act or any other rule or regulation thereunder; or (ii) Section
                                         5 of the Securities Act;

 

		(o)	He,
                                         she or it has never filed (as a registrant or issuer), or been named as an underwriter
                                         in any registration statement or Regulation A offering statement filed with the SEC that
                                         was the subject of a refusal order, stop order, or order suspending the Regulation A
                                         exemption, or is, currently, the subject of an investigation or proceeding to determine
                                         whether a stop order or suspension order should be issued;

 

		(p)	He,
                                         she or it has never been subject to a United States Postal Service false representation
                                         order, or is currently subject to a temporary restraining order or preliminary injunction
                                         with respect to conduct alleged by the United States Postal Service to constitute a scheme
                                         or device for obtaining money or property through the mail by means of false representations;

 

		(q)	He,
                                         she or it is not subject to a final order of a state securities commission (or an agency
                                         of officer of a state performing like functions); a state authority that supervises or
                                         examines banks, savings associations, or credit unions; a state insurance commission
                                         (or an agency or officer of a state performing like functions); an appropriate federal
                                         banking agency; the CFTC; or the National Credit Union Administration that bars the undersigned
                                         from: (i) association with an entity regulated by such commission, authority, agency
                                         or officer; (ii) engaging in the business of securities, insurance or banking; or (iii)
                                         engaging in savings association or credit union activities;

 

    14

     

    

 

		(r)	He,
                                         she or it is not subject to an order of the SEC entered pursuant to section 15(b) or
                                         15B(c) of the Securities Exchange Act of 1934 (the “Exchange Act”) or section
                                         203(e) or 203(f) of the Investment Advisers Act of 1940 (the “Advisers Act”)
                                         that: (i) suspends or revokes the undersigned’s registration as a broker, dealer,
                                         municipal securities dealer or investment adviser; (ii) places limitations on the activities,
                                         functions or operations of, or imposes civil money penalties on, such person; or (iii)
                                         bars the undersigned from being associated with any entity or from participating in the
                                         offering of any penny stock; and

 

		(s)	He,
                                         she or it has never been suspended or expelled from membership in, or suspended or barred
                                         from association with a member of, a securities self-regulatory organization (e.g., a
                                         registered national securities exchange or a registered national or affiliated securities
                                         association) for any act or omission to act constituting conduct inconsistent with just
                                         and equitable principles of trade.

 

 

11.
The undersigned has full right and power, without violating any agreement by which he, she or it is bound, to enter into this
letter agreement and to serve as a Director and/or officer of the Company.

 

12.
The undersigned hereby waives his, her or its right to exercise redemption rights with respect to any shares of Common Stock owned
or to be owned by the undersigned, directly or indirectly (or to sell such shares to the Company in a tender offer), whether purchased
by the undersigned prior to the IPO, in the IPO or in the aftermarket, and agrees that he, she or it will not seek redemption
with respect to or otherwise sell, such shares in connection with any vote to approve a Business Combination with respect thereto,
a vote to amend the provisions of the Company’s Amended and Restated Certificate of Incorporation, or a tender offer by
the Company prior to a Business Combination.

 

13.
The undersigned hereby agrees to not propose, or vote in favor of, an amendment to the Company’s Amended and Restated Certificate
of Incorporation with respect to the Company’s pre-Business Combination activities prior to the consummation of a Business
Combination unless the Company offers holders of IPO Shares the right to receive their pro rata portion of the funds then held
in the Trust Fund.

 

14.
In connection with Section 5-1401 of the General Obligations Law of the State of New York, this letter agreement shall be governed
by, and construed in accordance with, the laws of the State of New York without regard to principles of conflicts of law that
would result in the application of the substantive law of another jurisdiction. The parties hereto agree that any action, proceeding
or claim arising out of or relating in any way to this letter agreement shall be resolved through final and binding arbitration
in accordance with the International Arbitration Rules of the American Arbitration Association (“AAA”). The arbitration
shall be brought before the AAA International Center for Dispute Resolution’s offices in New York City, New York, will be
conducted in English and will be decided by a panel of three arbitrators selected from the AAA Commercial Disputes Panel and that
the arbitrator panel’s decision shall be final and enforceable by any court having jurisdiction over the party from whom
enforcement is sought. The cost of such arbitrators and arbitration services, together with the prevailing party’s legal
fees and expenses, shall be borne by the non-prevailing party or as otherwise directed by the arbitrators.

 

    15

     

    

 

15.
As used herein, (i) a “Business Combination” shall mean a merger, share exchange, asset acquisition,
contractual arrangement, share purchase, recapitalization, reorganization or other similar business combination with one or more
businesses or entities; (ii) “Insiders” shall mean all officers, directors and stockholders of the Company
immediately prior to the IPO; (iii) “Insider Shares” shall mean all of the shares of Common Stock of
the Company acquired by an Insider prior to the IPO and any shares of Common Stock underlying the Private Units; (iv) “IPO
Shares” shall mean the shares of Common Stock issued in the Company’s IPO; (v) [Intentionally Omitted;] (vi)
“Registration Statement” means the registration statement on Form S-1 filed by the Company with respect
to the IPO; and (vii) “Trust Fund” shall mean the trust fund into which a portion of the net proceeds
of the Company’s IPO will be deposited.

 

16.
Any notice, consent or request to be given in connection with any of the terms or provisions of this letter agreement shall be
in writing and shall be sent by express mail or similar private courier service, by certified mail (return receipt requested),
by hand delivery or facsimile transmission.

 

If
to the Representative:

 

Chardan
Capital Markets, LLC

17
State Street, Suite 1600

New
York, NY 10004

Attn:
George Kaufman

Facsimile:
(646) 465-9039

 

with
a copy (which copy shall not constitute notice) to:

 

Ellenoff
Grossman & Schole LLP 

1345
Avenue of the Americas

New
York, New York 10105

Attn:
Stuart Neuhauser, Esq. and Ari Edelman, Esq.

Facsimile.:
(212) 370-7889

 

If
to the Company:

 

Orisun
Acquisition Corp.

555
Madison Avenue, Room 543

New
York, NY 10022

Attn:
Wei Chen, Chief Executive Officer

 

with
a copy (which copy shall not constitute notice) to:

 

Loeb
& Loeb LLP

345
Park Avenue

New
York, NY 10154

Attn:
Giovanni Caruso, Esq.

Facsimile:
(212) 504-3013

 

    16

     

    

 

17.
No party hereto may assign either this letter agreement or any of its rights, interests, or obligations hereunder without the
prior written consent of the other party. Any purported assignment in violation of this paragraph shall be void and ineffectual
and shall not operate to transfer or assign any interest or title to the purported assignee. This letter agreement shall be binding
on the parties hereto and any successors and assigns thereof.

 

18.
This Letter Agreement constitutes the entire agreement and understanding of the parties hereto in respect of the subject matter
hereof and supersedes all prior understandings, agreements, or representations by or among the parties hereto, written or oral,
to the extent they relate in any way to the subject matter hereof or the transactions contemplated hereby. This Letter Agreement
may not be changed, amended, modified or waived (other than to correct a typographical error) as to any particular provision,
except by a written instrument executed by all parties hereto.

 

19.
The undersigned acknowledges and understands that the Underwriters and the Company will rely upon the agreements, representations
and warranties set forth herein in proceeding with the IPO. Nothing contained herein shall be deemed to render the Underwriters
a representative of, or a fiduciary with respect to, the Company, its stockholders or any creditor or vendor of the Company with
respect to the subject matter hereof.

 

    17

     

    

 

	 	/s/
    Lihua     Zheng
	 	Lihua
    Zheng

 

 

 

 

 

Signature
Page to Insider Letter

 

    18

     

    

 

August 2, 2019

 

Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

 

Chardan Capital Markets,
LLC

17 State Street, Suite 1600

New York, NY 10004

 

		Re:	Initial Public Offering

 

Ladies and Gentlemen:

 

This letter is
being delivered to you in accordance with the Underwriting Agreement (the “Underwriting Agreement”) entered
into by and between Orisun Acquisition Corp., a Delaware corporation (the “Company”), and Chardan Capital
Markets, LLC, as Representative (the “Representative”) of the several underwriters named on Schedule
A thereto (the “Underwriters”), relating to an underwritten initial public offering (the “IPO”)
of the Company’s units (the “Units”), each comprised of one share of common stock of the Company,
par value $0.00001 per share (the “Common Stock”), one redeemable warrant, each warrant entitling its
holder to purchase one-half (1/2) of a share of Common Stock at an exercise price of $11.50 per full share (the “Warrants”),
and one right to receive one-tenth (1/10) of a share of Common Stock (the “Rights”). Certain capitalized
terms used herein are defined in paragraph 14 hereof.

 

In order to induce the
Company and the Underwriters to enter into the Underwriting Agreement and to proceed with the IPO, and in recognition of the benefit
that such IPO will confer upon the undersigned, and for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the undersigned hereby agrees with the Company as follows:

 

1. If the Company solicits
approval of its stockholders of a Business Combination, the undersigned will vote all shares of Common Stock beneficially owned
by him, her or it, whether acquired before, in or after the IPO, in favor of such Business Combination.

 

2. (a) Unless the Company’s
stockholders are previously given the option to redeem their shares in connection with amending applicable documents to extend
the time that the Company has to complete a Business Combination and that the Company fails to consummate a Business Combination
within 12 months from the closing of the Company’s IPO (or, in the event that the Company extended the period of time to
consummate a business combination up to three times, each by an additional three months, within 21 months) from the closing of
the Company’s IPO, the undersigned shall take all reasonable steps to (i) cause the Trust Fund to be liquidated and distributed
to the holders of the IPO Shares and (ii) cause the Company to liquidate as soon as reasonably practicable.

 

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(b) The undersigned
hereby waives any and all right, title, interest or claim of any kind in or to any distribution of the Trust Fund and any remaining
net assets of the Company as a result of such liquidation with respect to his, her or its Insider Shares (“Claim”)
and hereby waives any Claim the undersigned may have in the future as a result of, or arising out of, any contracts or agreements
with the Company and will not seek recourse against the Trust Fund for any reason whatsoever.

 

[(c) Intentionally
Omitted.]

 

[(d) Intentionally
Omitted.]

 

3. [Intentionally Omitted.]

 

4. The undersigned will
escrow all of his, her or its Insider Shares pursuant to the terms of a Stock Escrow Agreement, which the Company will enter into
with the undersigned and an escrow agent acceptable to the Company.

 

5. [Intentionally Omitted.]

 

6. In order to minimize
potential conflicts of interest which may arise from multiple affiliations, the undersigned agrees to present to the Company for
its consideration, prior to presentation to any other person or entity, any suitable opportunity to acquire a target business,
until the earlier of the consummation by the Company of a Business Combination or the liquidation of the Company, subject to any
pre-existing fiduciary and contractual obligations the undersigned might have.

 

7. (a) The undersigned
acknowledges and agrees that prior to entering into a Business Combination with a target business that is affiliated with any Insiders
of the Company or their affiliates, including any company that is a portfolio company of, or otherwise affiliated with, or has
received financial investment from, an entity with which any Insider or their affiliates is affiliated, such transaction must be
approved by a majority of the Company’s disinterested independent directors and the Company must obtain an opinion from an
independent investment banking firm that such Business Combination is fair to the Company’s unaffiliated stockholders from
a financial point of view.

 

(b) The undersigned
hereby agrees and acknowledges that (i) each of the Underwriters and the Company may be irreparably injured in the event of a breach
of any of the obligations contained in this letter, (ii) monetary damages may not be an adequate remedy for such breach and (iii)
the non-breaching party shall be entitled to injunctive relief, in addition to any other remedy that such party may have in law
or in equity, in the event of such breach.

 

    20

     

    

 

8. Neither the undersigned,
any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to receive and will not accept
any compensation or other cash payment prior to, or for services rendered in connection with, the consummation of the Business
Combination; provided that the Company shall be allowed to repay working capital loans made by the undersigned to the Company
in cash upon consummation of the Business Combination. Notwithstanding the foregoing, the undersigned and any affiliate of the
undersigned shall be entitled to reimbursement from the Company for their out-of-pocket expenses incurred in connection with identifying,
investigating and consummating a Business Combination.

 

9. Neither the undersigned,
any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to receive or accept a finder’s
fee or any other compensation in the event the undersigned, any member of the family of the undersigned or any affiliate of the
undersigned originates a Business Combination.

 

10. The undersigned agrees
to be a director/officer of the Company until the earlier of the consummation by the Company of a Business Combination or the liquidation
of the Company. The undersigned’s biographical information previously furnished to the Company and the Representative is
true and accurate in all material respects, does not omit any material information with respect to the undersigned’s biography
and contains all of the information required to be disclosed pursuant to Item 401 of Regulation S-K, promulgated under the Securities
Act of 1933. The undersigned’s FINRA Questionnaire previously furnished to the Company and the Representative is true and
accurate in all material respects. The undersigned represents and warrants that:

 

		(a)	He, she or it has never had a petition under the federal bankruptcy laws or any state insolvency law been filed by or against
(i) him, her or it, or any partnership in which he or she was a general partner at or within two years before the time of filing;
or (ii) any corporation or business association of which he or she was an executive officer at or within two years before the time
of such filing;

 

		(b)	He, she or it has never had a receiver, fiscal agent or similar officer been appointed by a court for his business or property,
or any such partnership;

 

		(c)	He, she or it has never been convicted of fraud in a civil or criminal proceeding;

 

		(d)	He, she or it has never been convicted in a criminal proceeding or named the subject of a pending criminal proceeding (excluding
traffic violations and minor offenses);

 

		(e)	He, she or it has never been the subject of any order, judgment or decree, not subsequently reversed, suspended or vacated,
of any court of competent jurisdiction, permanently or temporarily enjoining or otherwise limiting him, her or it from (i) acting
as a futures commission merchant, introducing broker, commodity trading advisor, commodity pool operator, floor broker, leverage
transaction merchant, any other person regulated by the Commodity Futures Trading Commission (“CFTC”) or an associated
person of any of the foregoing, or as an investment adviser, underwriter, broker or dealer in securities, or as an affiliated person,
director or employee of any investment company, bank, savings and loan association or insurance company, or from engaging in or
continuing any conduct or practice in connection with any such activity; or (ii) engaging in any type of business practice;
or (iii) engaging in any activity in connection with the purchase or sale of any security or commodity or in connection with
any violation of federal or state securities or federal commodities laws;

 

    21

     

    

 

		(f)	He, she, or it has never been the subject of any order, judgment or decree, not subsequently reversed, suspended or vacated,
of any federal or state authority barring, suspending or otherwise limiting for more than 60 days his, her or its right to engage
in any activity described in 10(e)(i) above, or to be associated with persons engaged in any such activity;

 

		(g)	He, she, or it has never been found by a court of competent jurisdiction in a civil action or by the SEC to have violated any
federal or state securities law, where the judgment in such civil action or finding by the SEC has not been subsequently reversed,
suspended or vacated;

 

		(h)	He, she, or it has never been found by a court of competent jurisdiction in a civil action or by the CFTC to have violated
any federal commodities law, where the judgment in such civil action or finding by the CFTC has not been subsequently reversed,
suspended or vacated;

 

		(i)	He, she, or it has never been the subject of, or a party to, any Federal, State or foreign judicial or administrative order,
judgment, decree or finding, not subsequently reversed, suspended or vacated, relating to an alleged violation of (i) any Federal,
State or foreign securities or commodities law or regulation, (ii) any law or regulation respecting financial institutions or insurance
companies including, but not limited to, a temporary or permanent injunction, order of disgorgement or restitution, civil money
penalty or temporary or permanent cease-and desist order, or removal or prohibition order or (iii) any law or regulation prohibiting
mail or wire fraud or fraud in connection with any business entity;

 

		(j)	He, she or it has never been the subject of, or party to, any sanction or order, not subsequently reversed, suspended or vacated,
or any self-regulatory organization, any registered entity, or any equivalent exchange, association, entity or organization that
has disciplinary authority over its members or persons associated with a member;

 

		(k)	He, she or it has never been convicted of any felony or misdemeanor: (i) in connection with the purchase or sale of any security;
(ii) involving the making of any false filing with the SEC; or (iii) arising out of the conduct of the business of an underwriter,
broker, dealer, municipal securities dealer, investment advisor or paid solicitor of purchasers of securities;

 

    22

     

    

 

		(l)	He, she or it was never subject to a final order of a state or foreign securities commission (or an agency of officer of a
state performing like functions); a state or foreign authority that supervises or examines banks, savings associations, or credit
unions; a state or foreign insurance commission (or an agency or officer of a state performing like functions); an appropriate
federal or foreign banking agency; the CFTC; or the National Credit Union Administration that is based on a violation of any law
or regulation that prohibits fraudulent, manipulative, or deceptive conduct;

 

		(m)	He, she or it has never been subject to any order, judgment or decree of any court of competent jurisdiction, that, at the
time of the sale of the Units, restrained or enjoined him, her or it from engaging or continuing to engage in any conduct or practice:
(i) in connection with the purchase or sale of any security; (ii) involving the making of any false filing with the SEC or any
foreign regulatory agency with similar functions; or (iii) arising out of the conduct of the business of an underwriter, broker,
dealer, municipal securities dealer, investment adviser or paid solicitor of purchasers of securities;

 

		(n)	He, she or it has never been subject to any order of the SEC or any foreign regulatory agency with similar functions that orders
him, her or it to cease and desist from committing or causing a future violation of: (i) any scienter-based anti-fraud provision
of the federal securities laws, including, but not limited to, Section 17(a)(1) of the Securities Act, Section 10(b) of the Exchange
Act and Rule 10b-5 thereunder, Section 15(c) and Section 206(1) of the Advisers Act or any other rule or regulation thereunder;
or (ii) Section 5 of the Securities Act;

 

		(o)	He, she or it has never filed (as a registrant or issuer), or been named as an underwriter in any registration statement or
Regulation A offering statement filed with the SEC that was the subject of a refusal order, stop order, or order suspending the
Regulation A exemption, or is, currently, the subject of an investigation or proceeding to determine whether a stop order or suspension
order should be issued;

 

		(p)	He, she or it has never been subject to a United States Postal Service false representation order, or is currently subject
to a temporary restraining order or preliminary injunction with respect to conduct alleged by the United States Postal Service
to constitute a scheme or device for obtaining money or property through the mail by means of false representations;

 

		(q)	He, she or it is not subject to a final order of a state securities commission (or an agency of officer of a state performing
like functions); a state authority that supervises or examines banks, savings associations, or credit unions; a state insurance
commission (or an agency or officer of a state performing like functions); an appropriate federal banking agency; the CFTC; or
the National Credit Union Administration that bars the undersigned from: (i) association with an entity regulated by such commission,
authority, agency or officer; (ii) engaging in the business of securities, insurance or banking; or (iii) engaging in savings association
or credit union activities;

 

    23

     

    

 

		(r)	He, she or it is not subject to an order of the SEC entered pursuant to section 15(b) or 15B(c) of the Securities Exchange
Act of 1934 (the “Exchange Act”) or section 203(e) or 203(f) of the Investment Advisers Act of 1940 (the “Advisers
Act”) that: (i) suspends or revokes the undersigned’s registration as a broker, dealer, municipal securities dealer
or investment adviser; (ii) places limitations on the activities, functions or operations of, or imposes civil money penalties
on, such person; or (iii) bars the undersigned from being associated with any entity or from participating in the offering of any
penny stock; and

 

		(s)	He, she or it has never been suspended or expelled from membership in, or suspended or barred from association with a member
of, a securities self-regulatory organization (e.g., a registered national securities exchange or a registered national or affiliated
securities association) for any act or omission to act constituting conduct inconsistent with just and equitable principles of
trade.

 

 

11. The undersigned has
full right and power, without violating any agreement by which he, she or it is bound, to enter into this letter agreement and
to serve as a Director and/or officer of the Company.

 

12. The undersigned hereby
waives his, her or its right to exercise redemption rights with respect to any shares of Common Stock owned or to be owned by the
undersigned, directly or indirectly (or to sell such shares to the Company in a tender offer), whether purchased by the undersigned
prior to the IPO, in the IPO or in the aftermarket, and agrees that he, she or it will not seek redemption with respect to or otherwise
sell, such shares in connection with any vote to approve a Business Combination with respect thereto, a vote to amend the provisions
of the Company’s Amended and Restated Certificate of Incorporation, or a tender offer by the Company prior to a Business
Combination.

 

13. The undersigned hereby
agrees to not propose, or vote in favor of, an amendment to the Company’s Amended and Restated Certificate of Incorporation
with respect to the Company’s pre-Business Combination activities prior to the consummation of a Business Combination unless
the Company offers holders of IPO Shares the right to receive their pro rata portion of the funds then held in the Trust Fund.

 

14. In connection with
Section 5-1401 of the General Obligations Law of the State of New York, this letter agreement shall be governed by, and construed
in accordance with, the laws of the State of New York without regard to principles of conflicts of law that would result in the
application of the substantive law of another jurisdiction. The parties hereto agree that any action, proceeding or claim arising
out of or relating in any way to this letter agreement shall be resolved through final and binding arbitration in accordance with
the International Arbitration Rules of the American Arbitration Association (“AAA”). The arbitration shall be brought
before the AAA International Center for Dispute Resolution’s offices in New York City, New York, will be conducted in English
and will be decided by a panel of three arbitrators selected from the AAA Commercial Disputes Panel and that the arbitrator panel’s
decision shall be final and enforceable by any court having jurisdiction over the party from whom enforcement is sought. The cost
of such arbitrators and arbitration services, together with the prevailing party’s legal fees and expenses, shall be borne
by the non-prevailing party or as otherwise directed by the arbitrators.

 

    24

     

    

 

15. As used herein, (i)
a “Business Combination” shall mean a merger, share exchange, asset acquisition, contractual arrangement,
share purchase, recapitalization, reorganization or other similar business combination with one or more businesses or entities;
(ii) “Insiders” shall mean all officers, directors and stockholders of the Company immediately prior
to the IPO; (iii) “Insider Shares” shall mean all of the shares of Common Stock of the Company acquired
by an Insider prior to the IPO and any shares of Common Stock underlying the Private Units; (iv) “IPO Shares”
shall mean the shares of Common Stock issued in the Company’s IPO; (v) [Intentionally Omitted;] (vi) “Registration
Statement” means the registration statement on Form S-1 filed by the Company with respect to the IPO; and (vii) “Trust
Fund” shall mean the trust fund into which a portion of the net proceeds of the Company’s IPO will be deposited.

 

16. Any notice, consent
or request to be given in connection with any of the terms or provisions of this letter agreement shall be in writing and shall
be sent by express mail or similar private courier service, by certified mail (return receipt requested), by hand delivery or facsimile
transmission.

 

If to the Representative:

 

Chardan Capital Markets, LLC

17 State Street, Suite 1600

New York, NY 10004

Attn: George Kaufman

Facsimile: (646) 465-9039

 

with a copy (which copy shall not constitute
notice) to:

 

Ellenoff Grossman & Schole LLP 

1345 Avenue of the Americas

New York, New York 10105

Attn: Stuart Neuhauser, Esq. and Ari Edelman, Esq.

Facsimile.: (212) 370-7889

 

If to the Company:

 

Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

Attn: Wei Chen, Chief Executive Officer

 

    25

     

    

 

with a copy (which copy shall not constitute
notice) to:

 

Loeb & Loeb LLP

345 Park Avenue

New York, NY 10154

Attn: Giovanni Caruso, Esq.

Facsimile: (212) 504-3013

 

17. No party hereto may
assign either this letter agreement or any of its rights, interests, or obligations hereunder without the prior written consent
of the other party. Any purported assignment in violation of this paragraph shall be void and ineffectual and shall not operate
to transfer or assign any interest or title to the purported assignee. This letter agreement shall be binding on the parties hereto
and any successors and assigns thereof.

 

18. This Letter Agreement
constitutes the entire agreement and understanding of the parties hereto in respect of the subject matter hereof and supersedes
all prior understandings, agreements, or representations by or among the parties hereto, written or oral, to the extent they relate
in any way to the subject matter hereof or the transactions contemplated hereby. This Letter Agreement may not be changed, amended,
modified or waived (other than to correct a typographical error) as to any particular provision, except by a written instrument
executed by all parties hereto.

 

19. The undersigned acknowledges
and understands that the Underwriters and the Company will rely upon the agreements, representations and warranties set forth herein
in proceeding with the IPO. Nothing contained herein shall be deemed to render the Underwriters a representative of, or a fiduciary
with respect to, the Company, its stockholders or any creditor or vendor of the Company with respect to the subject matter hereof.

 

    26

     

    

 

	 	/s/ Ling Wu
	 	Ling Wu

 

 

 

 

 

Signature Page to Insider Letter

 

    27

     

    

 

August 2, 2019

 

Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

 

Chardan Capital Markets,
LLC

17 State Street, Suite 1600

New York, NY 10004

 

		Re:	Initial Public Offering

 

Ladies and Gentlemen:

 

This letter is
being delivered to you in accordance with the Underwriting Agreement (the “Underwriting Agreement”) entered
into by and between Orisun Acquisition Corp., a Delaware corporation (the “Company”), and Chardan Capital
Markets, LLC, as Representative (the “Representative”) of the several underwriters named on Schedule
A thereto (the “Underwriters”), relating to an underwritten initial public offering (the “IPO”)
of the Company’s units (the “Units”), each comprised of one share of common stock of the Company,
par value $0.00001 per share (the “Common Stock”), one redeemable warrant, each warrant entitling its
holder to purchase one-half (1/2) of a share of Common Stock at an exercise price of $11.50 per full share (the “Warrants”),
and one right to receive one-tenth (1/10) of a share of Common Stock (the “Rights”). Certain capitalized
terms used herein are defined in paragraph 14 hereof.

 

In order to induce the
Company and the Underwriters to enter into the Underwriting Agreement and to proceed with the IPO, and in recognition of the benefit
that such IPO will confer upon the undersigned, and for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the undersigned hereby agrees with the Company as follows:

 

1. If the Company solicits
approval of its stockholders of a Business Combination, the undersigned will vote all shares of Common Stock beneficially owned
by him, her or it, whether acquired before, in or after the IPO, in favor of such Business Combination.

 

2. (a) Unless the Company’s
stockholders are previously given the option to redeem their shares in connection with amending applicable documents to extend
the time that the Company has to complete a Business Combination and that the Company fails to consummate a Business Combination
within 12 months from the closing of the Company’s IPO (or, in the event that the Company extended the period of time to
consummate a business combination up to three times, each by an additional three months, within 21 months) from the closing of
the Company’s IPO, the undersigned shall take all reasonable steps to (i) cause the Trust Fund to be liquidated and distributed
to the holders of the IPO Shares and (ii) cause the Company to liquidate as soon as reasonably practicable.

 

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(b) The undersigned
hereby waives any and all right, title, interest or claim of any kind in or to any distribution of the Trust Fund and any remaining
net assets of the Company as a result of such liquidation with respect to his, her or its Insider Shares (“Claim”)
and hereby waives any Claim the undersigned may have in the future as a result of, or arising out of, any contracts or agreements
with the Company and will not seek recourse against the Trust Fund for any reason whatsoever.

 

[(c) Intentionally
Omitted.]

 

[(d) Intentionally
Omitted.]

 

3. [Intentionally Omitted.]

 

4. The undersigned will
escrow all of his, her or its Insider Shares pursuant to the terms of a Stock Escrow Agreement, which the Company will enter into
with the undersigned and an escrow agent acceptable to the Company.

 

5. [Intentionally Omitted.]

 

6. In order to minimize
potential conflicts of interest which may arise from multiple affiliations, the undersigned agrees to present to the Company for
its consideration, prior to presentation to any other person or entity, any suitable opportunity to acquire a target business,
until the earlier of the consummation by the Company of a Business Combination or the liquidation of the Company, subject to any
pre-existing fiduciary and contractual obligations the undersigned might have.

 

7. (a) The undersigned
acknowledges and agrees that prior to entering into a Business Combination with a target business that is affiliated with any Insiders
of the Company or their affiliates, including any company that is a portfolio company of, or otherwise affiliated with, or has
received financial investment from, an entity with which any Insider or their affiliates is affiliated, such transaction must be
approved by a majority of the Company’s disinterested independent directors and the Company must obtain an opinion from an
independent investment banking firm that such Business Combination is fair to the Company’s unaffiliated stockholders from
a financial point of view.

 

(b) The undersigned
hereby agrees and acknowledges that (i) each of the Underwriters and the Company may be irreparably injured in the event of a breach
of any of the obligations contained in this letter, (ii) monetary damages may not be an adequate remedy for such breach and (iii)
the non-breaching party shall be entitled to injunctive relief, in addition to any other remedy that such party may have in law
or in equity, in the event of such breach.

 

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8. Neither the undersigned,
any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to receive and will not accept
any compensation or other cash payment prior to, or for services rendered in connection with, the consummation of the Business
Combination; provided that the Company shall be allowed to repay working capital loans made by the undersigned to the Company
in cash upon consummation of the Business Combination. Notwithstanding the foregoing, the undersigned and any affiliate of the
undersigned shall be entitled to reimbursement from the Company for their out-of-pocket expenses incurred in connection with identifying,
investigating and consummating a Business Combination.

 

9. Neither the undersigned,
any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to receive or accept a finder’s
fee or any other compensation in the event the undersigned, any member of the family of the undersigned or any affiliate of the
undersigned originates a Business Combination.

 

10. The undersigned agrees
to be a director/officer of the Company until the earlier of the consummation by the Company of a Business Combination or the liquidation
of the Company. The undersigned’s biographical information previously furnished to the Company and the Representative is
true and accurate in all material respects, does not omit any material information with respect to the undersigned’s biography
and contains all of the information required to be disclosed pursuant to Item 401 of Regulation S-K, promulgated under the Securities
Act of 1933. The undersigned’s FINRA Questionnaire previously furnished to the Company and the Representative is true and
accurate in all material respects. The undersigned represents and warrants that:

 

		(a)	He, she or it has never had a petition under the federal bankruptcy laws or any state insolvency
law been filed by or against (i) him, her or it, or any partnership in which he or she was a general partner at or within two years
before the time of filing; or (ii) any corporation or business association of which he or she was an executive officer at or within
two years before the time of such filing;

 

		(b)	He, she or it has never had a receiver, fiscal agent or similar officer been appointed by a court
for his business or property, or any such partnership;

 

		(c)	He, she or it has never been convicted of fraud in a civil or criminal proceeding;

 

		(d)	He, she or it has never been convicted in a criminal proceeding or named the subject of a pending
criminal proceeding (excluding traffic violations and minor offenses);

 

		(e)	He, she or it has never been the subject of any order, judgment or decree, not subsequently reversed,
suspended or vacated, of any court of competent jurisdiction, permanently or temporarily enjoining or otherwise limiting him, her
or it from (i) acting as a futures commission merchant, introducing broker, commodity trading advisor, commodity pool operator,
floor broker, leverage transaction merchant, any other person regulated by the Commodity Futures Trading Commission (“CFTC”)
or an associated person of any of the foregoing, or as an investment adviser, underwriter, broker or dealer in securities, or as
an affiliated person, director or employee of any investment company, bank, savings and loan association or insurance company,
or from engaging in or continuing any conduct or practice in connection with any such activity; or (ii) engaging in any type
of business practice; or (iii) engaging in any activity in connection with the purchase or sale of any security or commodity
or in connection with any violation of federal or state securities or federal commodities laws;

 

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		(f)	He, she, or it has never been the subject of any order, judgment or decree, not subsequently reversed,
suspended or vacated, of any federal or state authority barring, suspending or otherwise limiting for more than 60 days his, her
or its right to engage in any activity described in 10(e)(i) above, or to be associated with persons engaged in any such activity;

 

		(g)	He, she, or it has never been found by a court of competent jurisdiction in a civil action or by
the SEC to have violated any federal or state securities law, where the judgment in such civil action or finding by the SEC has
not been subsequently reversed, suspended or vacated;

 

		(h)	He, she, or it has never been found by a court of competent jurisdiction in a civil action or by
the CFTC to have violated any federal commodities law, where the judgment in such civil action or finding by the CFTC has not been
subsequently reversed, suspended or vacated;

 

		(i)	He, she, or it has never been the subject of, or a party to, any Federal, State or foreign judicial
or administrative order, judgment, decree or finding, not subsequently reversed, suspended or vacated, relating to an alleged violation
of (i) any Federal, State or foreign securities or commodities law or regulation, (ii) any law or regulation respecting financial
institutions or insurance companies including, but not limited to, a temporary or permanent injunction, order of disgorgement or
restitution, civil money penalty or temporary or permanent cease-and desist order, or removal or prohibition order or (iii) any
law or regulation prohibiting mail or wire fraud or fraud in connection with any business entity;

 

		(j)	He, she or it has never been the subject of, or party to, any sanction or order, not subsequently
reversed, suspended or vacated, or any self-regulatory organization, any registered entity, or any equivalent exchange, association,
entity or organization that has disciplinary authority over its members or persons associated with a member;

 

		(k)	He, she or it has never been convicted of any felony or misdemeanor: (i) in connection with the
purchase or sale of any security; (ii) involving the making of any false filing with the SEC; or (iii) arising out of the conduct
of the business of an underwriter, broker, dealer, municipal securities dealer, investment advisor or paid solicitor of purchasers
of securities;

 

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		(l)	He, she or it was never subject to a final order of a state or foreign securities commission (or
an agency of officer of a state performing like functions); a state or foreign authority that supervises or examines banks, savings
associations, or credit unions; a state or foreign insurance commission (or an agency or officer of a state performing like functions);
an appropriate federal or foreign banking agency; the CFTC; or the National Credit Union Administration that is based on a violation
of any law or regulation that prohibits fraudulent, manipulative, or deceptive conduct;

 

		(m)	He, she or it has never been subject to any order, judgment or decree of any court of competent
jurisdiction, that, at the time of the sale of the Units, restrained or enjoined him, her or it from engaging or continuing to
engage in any conduct or practice: (i) in connection with the purchase or sale of any security; (ii) involving the making of any
false filing with the SEC or any foreign regulatory agency with similar functions; or (iii) arising out of the conduct of the business
of an underwriter, broker, dealer, municipal securities dealer, investment adviser or paid solicitor of purchasers of securities;

 

		(n)	He, she or it has never been subject to any order of the SEC or any foreign regulatory agency with
similar functions that orders him, her or it to cease and desist from committing or causing a future violation of: (i) any scienter-based
anti-fraud provision of the federal securities laws, including, but not limited to, Section 17(a)(1) of the Securities Act, Section
10(b) of the Exchange Act and Rule 10b-5 thereunder, Section 15(c) and Section 206(1) of the Advisers Act or any other rule or
regulation thereunder; or (ii) Section 5 of the Securities Act;

 

		(o)	He, she or it has never filed (as a registrant or issuer), or been named as an underwriter in any
registration statement or Regulation A offering statement filed with the SEC that was the subject of a refusal order, stop order,
or order suspending the Regulation A exemption, or is, currently, the subject of an investigation or proceeding to determine whether
a stop order or suspension order should be issued;

 

		(p)	He, she or it has never been subject to a United States Postal Service false representation order,
or is currently subject to a temporary restraining order or preliminary injunction with respect to conduct alleged by the United
States Postal Service to constitute a scheme or device for obtaining money or property through the mail by means of false representations;

 

		(q)	He, she or it is not subject to a final order of a state securities commission (or an agency of
officer of a state performing like functions); a state authority that supervises or examines banks, savings associations, or credit
unions; a state insurance commission (or an agency or officer of a state performing like functions); an appropriate federal banking
agency; the CFTC; or the National Credit Union Administration that bars the undersigned from: (i) association with an entity regulated
by such commission, authority, agency or officer; (ii) engaging in the business of securities, insurance or banking; or (iii) engaging
in savings association or credit union activities;

 

    32

     

    

 

		(r)	He, she or it is not subject to an order of the SEC entered pursuant to section 15(b) or 15B(c)
of the Securities Exchange Act of 1934 (the “Exchange Act”) or section 203(e) or 203(f) of the Investment Advisers
Act of 1940 (the “Advisers Act”) that: (i) suspends or revokes the undersigned’s registration as a broker, dealer,
municipal securities dealer or investment adviser; (ii) places limitations on the activities, functions or operations of, or imposes
civil money penalties on, such person; or (iii) bars the undersigned from being associated with any entity or from participating
in the offering of any penny stock; and

 

		(s)	He, she or it has never been suspended or expelled from membership in, or suspended or barred from
association with a member of, a securities self-regulatory organization (e.g., a registered national securities exchange or a registered
national or affiliated securities association) for any act or omission to act constituting conduct inconsistent with just and equitable
principles of trade.

 

 

11. The undersigned has
full right and power, without violating any agreement by which he, she or it is bound, to enter into this letter agreement and
to serve as a Director and/or officer of the Company.

 

12. The undersigned hereby
waives his, her or its right to exercise redemption rights with respect to any shares of Common Stock owned or to be owned by the
undersigned, directly or indirectly (or to sell such shares to the Company in a tender offer), whether purchased by the undersigned
prior to the IPO, in the IPO or in the aftermarket, and agrees that he, she or it will not seek redemption with respect to or otherwise
sell, such shares in connection with any vote to approve a Business Combination with respect thereto, a vote to amend the provisions
of the Company’s Amended and Restated Certificate of Incorporation, or a tender offer by the Company prior to a Business
Combination.

 

13. The undersigned hereby
agrees to not propose, or vote in favor of, an amendment to the Company’s Amended and Restated Certificate of Incorporation
with respect to the Company’s pre-Business Combination activities prior to the consummation of a Business Combination unless
the Company offers holders of IPO Shares the right to receive their pro rata portion of the funds then held in the Trust Fund.

 

14. In connection with
Section 5-1401 of the General Obligations Law of the State of New York, this letter agreement shall be governed by, and construed
in accordance with, the laws of the State of New York without regard to principles of conflicts of law that would result in the
application of the substantive law of another jurisdiction. The parties hereto agree that any action, proceeding or claim arising
out of or relating in any way to this letter agreement shall be resolved through final and binding arbitration in accordance with
the International Arbitration Rules of the American Arbitration Association (“AAA”). The arbitration shall be brought
before the AAA International Center for Dispute Resolution’s offices in New York City, New York, will be conducted in English
and will be decided by a panel of three arbitrators selected from the AAA Commercial Disputes Panel and that the arbitrator panel’s
decision shall be final and enforceable by any court having jurisdiction over the party from whom enforcement is sought. The cost
of such arbitrators and arbitration services, together with the prevailing party’s legal fees and expenses, shall be borne
by the non-prevailing party or as otherwise directed by the arbitrators.

 

    33

     

    

 

15. As used herein, (i)
a “Business Combination” shall mean a merger, share exchange, asset acquisition, contractual arrangement,
share purchase, recapitalization, reorganization or other similar business combination with one or more businesses or entities;
(ii) “Insiders” shall mean all officers, directors and stockholders of the Company immediately prior
to the IPO; (iii) “Insider Shares” shall mean all of the shares of Common Stock of the Company acquired
by an Insider prior to the IPO and any shares of Common Stock underlying the Private Units; (iv) “IPO Shares”
shall mean the shares of Common Stock issued in the Company’s IPO; (v) [Intentionally Omitted;] (vi) “Registration
Statement” means the registration statement on Form S-1 filed by the Company with respect to the IPO; and (vii) “Trust
Fund” shall mean the trust fund into which a portion of the net proceeds of the Company’s IPO will be deposited.

 

16. Any notice, consent
or request to be given in connection with any of the terms or provisions of this letter agreement shall be in writing and shall
be sent by express mail or similar private courier service, by certified mail (return receipt requested), by hand delivery or facsimile
transmission.

 

If to the Representative:

 

Chardan Capital Markets, LLC

17 State Street, Suite 1600

New York, NY 10004

Attn: George Kaufman

Facsimile: (646) 465-9039

 

with a copy (which copy shall not constitute
notice) to:

 

Ellenoff Grossman & Schole LLP 

1345 Avenue of the Americas

New York, New York 10105

Attn: Stuart Neuhauser, Esq. and Ari Edelman, Esq.

Facsimile.: (212) 370-7889

 

If to the Company:

 

Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

Attn: Wei Chen, Chief Executive Officer

 

    34

     

    

 

with a copy (which copy shall not constitute
notice) to:

 

Loeb & Loeb LLP

345 Park Avenue

New York, NY 10154

Attn: Giovanni Caruso, Esq.

Facsimile: (212) 504-3013

 

17. No party hereto may
assign either this letter agreement or any of its rights, interests, or obligations hereunder without the prior written consent
of the other party. Any purported assignment in violation of this paragraph shall be void and ineffectual and shall not operate
to transfer or assign any interest or title to the purported assignee. This letter agreement shall be binding on the parties hereto
and any successors and assigns thereof.

 

18. This Letter Agreement
constitutes the entire agreement and understanding of the parties hereto in respect of the subject matter hereof and supersedes
all prior understandings, agreements, or representations by or among the parties hereto, written or oral, to the extent they relate
in any way to the subject matter hereof or the transactions contemplated hereby. This Letter Agreement may not be changed, amended,
modified or waived (other than to correct a typographical error) as to any particular provision, except by a written instrument
executed by all parties hereto.

 

19. The undersigned acknowledges
and understands that the Underwriters and the Company will rely upon the agreements, representations and warranties set forth herein
in proceeding with the IPO. Nothing contained herein shall be deemed to render the Underwriters a representative of, or a fiduciary
with respect to, the Company, its stockholders or any creditor or vendor of the Company with respect to the subject matter hereof.

 

    35

     

    

 

	 	/s/
    Lu Zhou
	 	Lu Zhou 

 

 

 

 

 

Signature Page to Insider Letter

 

    36

     

    

 

August 2, 2019

 

Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

 

Chardan Capital Markets,
LLC

17 State Street, Suite 1600

New York, NY 10004

 

		Re:	Initial Public Offering

 

Ladies and Gentlemen:

 

This letter is
being delivered to you in accordance with the Underwriting Agreement (the “Underwriting Agreement”) entered
into by and between Orisun Acquisition Corp., a Delaware corporation (the “Company”), and Chardan Capital
Markets, LLC, as Representative (the “Representative”) of the several underwriters named on Schedule
A thereto (the “Underwriters”), relating to an underwritten initial public offering (the “IPO”)
of the Company’s units (the “Units”), each comprised of one share of common stock of the Company,
par value $0.00001 per share (the “Common Stock”), one redeemable warrant, each warrant entitling its
holder to purchase one-half (1/2) of a share of Common Stock at an exercise price of $11.50 per full share (the “Warrants”),
and one right to receive one-tenth (1/10) of a share of Common Stock (the “Rights”). Certain capitalized
terms used herein are defined in paragraph 14 hereof.

 

In order to induce the
Company and the Underwriters to enter into the Underwriting Agreement and to proceed with the IPO, and in recognition of the benefit
that such IPO will confer upon the undersigned, and for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the undersigned hereby agrees with the Company as follows:

 

1. If the Company solicits
approval of its stockholders of a Business Combination, the undersigned will vote all shares of Common Stock beneficially owned
by him, her or it, whether acquired before, in or after the IPO, in favor of such Business Combination.

 

2. (a) Unless the Company’s
stockholders are previously given the option to redeem their shares in connection with amending applicable documents to extend
the time that the Company has to complete a Business Combination and that the Company fails to consummate a Business Combination
within 12 months from the closing of the Company’s IPO (or, in the event that the Company extended the period of time to
consummate a business combination up to three times, each by an additional three months, within 21 months) from the closing of
the Company’s IPO, the undersigned shall take all reasonable steps to (i) cause the Trust Fund to be liquidated and distributed
to the holders of the IPO Shares and (ii) cause the Company to liquidate as soon as reasonably practicable.

 

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(b) The undersigned
hereby waives any and all right, title, interest or claim of any kind in or to any distribution of the Trust Fund and any remaining
net assets of the Company as a result of such liquidation with respect to his, her or its Insider Shares (“Claim”)
and hereby waives any Claim the undersigned may have in the future as a result of, or arising out of, any contracts or agreements
with the Company and will not seek recourse against the Trust Fund for any reason whatsoever.

 

[(c) Intentionally
Omitted.]

 

[(d) Intentionally
Omitted.]

 

3. [Intentionally Omitted.]

 

4. The undersigned will
escrow all of his, her or its Insider Shares pursuant to the terms of a Stock Escrow Agreement, which the Company will enter into
with the undersigned and an escrow agent acceptable to the Company.

 

5. [Intentionally Omitted.]

 

6. In order to minimize
potential conflicts of interest which may arise from multiple affiliations, the undersigned agrees to present to the Company for
its consideration, prior to presentation to any other person or entity, any suitable opportunity to acquire a target business,
until the earlier of the consummation by the Company of a Business Combination or the liquidation of the Company, subject to any
pre-existing fiduciary and contractual obligations the undersigned might have.

 

7. (a) The undersigned
acknowledges and agrees that prior to entering into a Business Combination with a target business that is affiliated with any Insiders
of the Company or their affiliates, including any company that is a portfolio company of, or otherwise affiliated with, or has
received financial investment from, an entity with which any Insider or their affiliates is affiliated, such transaction must be
approved by a majority of the Company’s disinterested independent directors and the Company must obtain an opinion from an
independent investment banking firm that such Business Combination is fair to the Company’s unaffiliated stockholders from
a financial point of view.

 

(b) The undersigned
hereby agrees and acknowledges that (i) each of the Underwriters and the Company may be irreparably injured in the event of a breach
of any of the obligations contained in this letter, (ii) monetary damages may not be an adequate remedy for such breach and (iii)
the non-breaching party shall be entitled to injunctive relief, in addition to any other remedy that such party may have in law
or in equity, in the event of such breach.

 

    38

     

    

 

8. Neither the undersigned,
any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to receive and will not accept
any compensation or other cash payment prior to, or for services rendered in connection with, the consummation of the Business
Combination; provided that the Company shall be allowed to repay working capital loans made by the undersigned to the Company
in cash upon consummation of the Business Combination. Notwithstanding the foregoing, the undersigned and any affiliate of the
undersigned shall be entitled to reimbursement from the Company for their out-of-pocket expenses incurred in connection with identifying,
investigating and consummating a Business Combination.

 

9. Neither the undersigned,
any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to receive or accept a finder’s
fee or any other compensation in the event the undersigned, any member of the family of the undersigned or any affiliate of the
undersigned originates a Business Combination.

 

10. The undersigned agrees
to be a director/officer of the Company until the earlier of the consummation by the Company of a Business Combination or the liquidation
of the Company. The undersigned’s biographical information previously furnished to the Company and the Representative is
true and accurate in all material respects, does not omit any material information with respect to the undersigned’s biography
and contains all of the information required to be disclosed pursuant to Item 401 of Regulation S-K, promulgated under the Securities
Act of 1933. The undersigned’s FINRA Questionnaire previously furnished to the Company and the Representative is true and
accurate in all material respects. The undersigned represents and warrants that:

 

		(a)	He, she or it has never had a petition under the federal bankruptcy laws or any state insolvency
law been filed by or against (i) him, her or it, or any partnership in which he or she was a general partner at or within two years
before the time of filing; or (ii) any corporation or business association of which he or she was an executive officer at or within
two years before the time of such filing;

 

		(b)	He, she or it has never had a receiver, fiscal agent or similar officer been appointed by a court
for his business or property, or any such partnership;

 

		(c)	He, she or it has never been convicted of fraud in a civil or criminal proceeding;

 

		(d)	He, she or it has never been convicted in a criminal proceeding or named the subject of a pending
criminal proceeding (excluding traffic violations and minor offenses);

 

		(e)	He, she or it has never been the subject of any order, judgment or decree, not subsequently reversed,
suspended or vacated, of any court of competent jurisdiction, permanently or temporarily enjoining or otherwise limiting him, her
or it from (i) acting as a futures commission merchant, introducing broker, commodity trading advisor, commodity pool operator,
floor broker, leverage transaction merchant, any other person regulated by the Commodity Futures Trading Commission (“CFTC”)
or an associated person of any of the foregoing, or as an investment adviser, underwriter, broker or dealer in securities, or as
an affiliated person, director or employee of any investment company, bank, savings and loan association or insurance company,
or from engaging in or continuing any conduct or practice in connection with any such activity; or (ii) engaging in any type
of business practice; or (iii) engaging in any activity in connection with the purchase or sale of any security or commodity
or in connection with any violation of federal or state securities or federal commodities laws;

 

    39

     

    

 

		(f)	He, she, or it has never been the subject of any order, judgment or decree, not subsequently reversed,
suspended or vacated, of any federal or state authority barring, suspending or otherwise limiting for more than 60 days his, her
or its right to engage in any activity described in 10(e)(i) above, or to be associated with persons engaged in any such activity;

 

		(g)	He, she, or it has never been found by a court of competent jurisdiction in a civil action or by
the SEC to have violated any federal or state securities law, where the judgment in such civil action or finding by the SEC has
not been subsequently reversed, suspended or vacated;

 

		(h)	He, she, or it has never been found by a court of competent jurisdiction in a civil action or by
the CFTC to have violated any federal commodities law, where the judgment in such civil action or finding by the CFTC has not been
subsequently reversed, suspended or vacated;

 

		(i)	He, she, or it has never been the subject of, or a party to, any Federal, State or foreign judicial
or administrative order, judgment, decree or finding, not subsequently reversed, suspended or vacated, relating to an alleged violation
of (i) any Federal, State or foreign securities or commodities law or regulation, (ii) any law or regulation respecting financial
institutions or insurance companies including, but not limited to, a temporary or permanent injunction, order of disgorgement or
restitution, civil money penalty or temporary or permanent cease-and desist order, or removal or prohibition order or (iii) any
law or regulation prohibiting mail or wire fraud or fraud in connection with any business entity;

 

		(j)	He, she or it has never been the subject of, or party to, any sanction or order, not subsequently
reversed, suspended or vacated, or any self-regulatory organization, any registered entity, or any equivalent exchange, association,
entity or organization that has disciplinary authority over its members or persons associated with a member;

 

		(k)	He, she or it has never been convicted of any felony or misdemeanor: (i) in connection with the
purchase or sale of any security; (ii) involving the making of any false filing with the SEC; or (iii) arising out of the conduct
of the business of an underwriter, broker, dealer, municipal securities dealer, investment advisor or paid solicitor of purchasers
of securities;

 

    40

     

    

 

		(l)	He, she or it was never subject to a final order of a state or foreign securities commission (or
an agency of officer of a state performing like functions); a state or foreign authority that supervises or examines banks, savings
associations, or credit unions; a state or foreign insurance commission (or an agency or officer of a state performing like functions);
an appropriate federal or foreign banking agency; the CFTC; or the National Credit Union Administration that is based on a violation
of any law or regulation that prohibits fraudulent, manipulative, or deceptive conduct;

 

		(m)	He, she or it has never been subject to any order, judgment or decree of any court of competent
jurisdiction, that, at the time of the sale of the Units, restrained or enjoined him, her or it from engaging or continuing to
engage in any conduct or practice: (i) in connection with the purchase or sale of any security; (ii) involving the making of any
false filing with the SEC or any foreign regulatory agency with similar functions; or (iii) arising out of the conduct of the business
of an underwriter, broker, dealer, municipal securities dealer, investment adviser or paid solicitor of purchasers of securities;

 

		(n)	He, she or it has never been subject to any order of the SEC or any foreign regulatory agency with
similar functions that orders him, her or it to cease and desist from committing or causing a future violation of: (i) any scienter-based
anti-fraud provision of the federal securities laws, including, but not limited to, Section 17(a)(1) of the Securities Act, Section
10(b) of the Exchange Act and Rule 10b-5 thereunder, Section 15(c) and Section 206(1) of the Advisers Act or any other rule or
regulation thereunder; or (ii) Section 5 of the Securities Act;

 

		(o)	He, she or it has never filed (as a registrant or issuer), or been named as an underwriter in any
registration statement or Regulation A offering statement filed with the SEC that was the subject of a refusal order, stop order,
or order suspending the Regulation A exemption, or is, currently, the subject of an investigation or proceeding to determine whether
a stop order or suspension order should be issued;

 

		(p)	He, she or it has never been subject to a United States Postal Service false representation order,
or is currently subject to a temporary restraining order or preliminary injunction with respect to conduct alleged by the United
States Postal Service to constitute a scheme or device for obtaining money or property through the mail by means of false representations;

 

		(q)	He, she or it is not subject to a final order of a state securities commission (or an agency of
officer of a state performing like functions); a state authority that supervises or examines banks, savings associations, or credit
unions; a state insurance commission (or an agency or officer of a state performing like functions); an appropriate federal banking
agency; the CFTC; or the National Credit Union Administration that bars the undersigned from: (i) association with an entity regulated
by such commission, authority, agency or officer; (ii) engaging in the business of securities, insurance or banking; or (iii) engaging
in savings association or credit union activities;

 

    41

     

    

 

		(r)	He, she or it is not subject to an order of the SEC entered pursuant to section 15(b) or 15B(c)
of the Securities Exchange Act of 1934 (the “Exchange Act”) or section 203(e) or 203(f) of the Investment Advisers
Act of 1940 (the “Advisers Act”) that: (i) suspends or revokes the undersigned’s registration as a broker, dealer,
municipal securities dealer or investment adviser; (ii) places limitations on the activities, functions or operations of, or imposes
civil money penalties on, such person; or (iii) bars the undersigned from being associated with any entity or from participating
in the offering of any penny stock; and

 

		(s)	He, she or it has never been suspended or expelled from membership in, or suspended or barred from
association with a member of, a securities self-regulatory organization (e.g., a registered national securities exchange or a registered
national or affiliated securities association) for any act or omission to act constituting conduct inconsistent with just and equitable
principles of trade.

 

 

11. The undersigned has
full right and power, without violating any agreement by which he, she or it is bound, to enter into this letter agreement and
to serve as a Director and/or officer of the Company.

 

12. The undersigned hereby
waives his, her or its right to exercise redemption rights with respect to any shares of Common Stock owned or to be owned by the
undersigned, directly or indirectly (or to sell such shares to the Company in a tender offer), whether purchased by the undersigned
prior to the IPO, in the IPO or in the aftermarket, and agrees that he, she or it will not seek redemption with respect to or otherwise
sell, such shares in connection with any vote to approve a Business Combination with respect thereto, a vote to amend the provisions
of the Company’s Amended and Restated Certificate of Incorporation, or a tender offer by the Company prior to a Business
Combination.

 

13. The undersigned hereby
agrees to not propose, or vote in favor of, an amendment to the Company’s Amended and Restated Certificate of Incorporation
with respect to the Company’s pre-Business Combination activities prior to the consummation of a Business Combination unless
the Company offers holders of IPO Shares the right to receive their pro rata portion of the funds then held in the Trust Fund.

 

14. In connection with
Section 5-1401 of the General Obligations Law of the State of New York, this letter agreement shall be governed by, and construed
in accordance with, the laws of the State of New York without regard to principles of conflicts of law that would result in the
application of the substantive law of another jurisdiction. The parties hereto agree that any action, proceeding or claim arising
out of or relating in any way to this letter agreement shall be resolved through final and binding arbitration in accordance with
the International Arbitration Rules of the American Arbitration Association (“AAA”). The arbitration shall be brought
before the AAA International Center for Dispute Resolution’s offices in New York City, New York, will be conducted in English
and will be decided by a panel of three arbitrators selected from the AAA Commercial Disputes Panel and that the arbitrator panel’s
decision shall be final and enforceable by any court having jurisdiction over the party from whom enforcement is sought. The cost
of such arbitrators and arbitration services, together with the prevailing party’s legal fees and expenses, shall be borne
by the non-prevailing party or as otherwise directed by the arbitrators.

 

    42

     

    

 

15. As used herein, (i)
a “Business Combination” shall mean a merger, share exchange, asset acquisition, contractual arrangement,
share purchase, recapitalization, reorganization or other similar business combination with one or more businesses or entities;
(ii) “Insiders” shall mean all officers, directors and stockholders of the Company immediately prior
to the IPO; (iii) “Insider Shares” shall mean all of the shares of Common Stock of the Company acquired
by an Insider prior to the IPO and any shares of Common Stock underlying the Private Units; (iv) “IPO Shares”
shall mean the shares of Common Stock issued in the Company’s IPO; (v) [Intentionally Omitted;] (vi) “Registration
Statement” means the registration statement on Form S-1 filed by the Company with respect to the IPO; and (vii) “Trust
Fund” shall mean the trust fund into which a portion of the net proceeds of the Company’s IPO will be deposited.

 

16. Any notice, consent
or request to be given in connection with any of the terms or provisions of this letter agreement shall be in writing and shall
be sent by express mail or similar private courier service, by certified mail (return receipt requested), by hand delivery or facsimile
transmission.

 

If to the Representative:

 

Chardan Capital Markets, LLC

17 State Street, Suite 1600

New York, NY 10004

Attn: George Kaufman

Facsimile: (646) 465-9039

 

with a copy (which copy shall not constitute
notice) to:

 

Ellenoff Grossman & Schole LLP 

1345 Avenue of the Americas

New York, New York 10105

Attn: Stuart Neuhauser, Esq. and Ari Edelman, Esq.

Facsimile.: (212) 370-7889

 

If to the Company:

 

Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

Attn: Wei Chen, Chief Executive Officer

 

    43

     

    

 

with a copy (which copy shall not constitute
notice) to:

 

Loeb & Loeb LLP

345 Park Avenue

New York, NY 10154

Attn: Giovanni Caruso, Esq.

Facsimile: (212) 504-3013

 

17. No party hereto may
assign either this letter agreement or any of its rights, interests, or obligations hereunder without the prior written consent
of the other party. Any purported assignment in violation of this paragraph shall be void and ineffectual and shall not operate
to transfer or assign any interest or title to the purported assignee. This letter agreement shall be binding on the parties hereto
and any successors and assigns thereof.

 

18. This Letter Agreement
constitutes the entire agreement and understanding of the parties hereto in respect of the subject matter hereof and supersedes
all prior understandings, agreements, or representations by or among the parties hereto, written or oral, to the extent they relate
in any way to the subject matter hereof or the transactions contemplated hereby. This Letter Agreement may not be changed, amended,
modified or waived (other than to correct a typographical error) as to any particular provision, except by a written instrument
executed by all parties hereto.

 

19. The undersigned acknowledges
and understands that the Underwriters and the Company will rely upon the agreements, representations and warranties set forth herein
in proceeding with the IPO. Nothing contained herein shall be deemed to render the Underwriters a representative of, or a fiduciary
with respect to, the Company, its stockholders or any creditor or vendor of the Company with respect to the subject matter hereof.

 

    44

     

    

 

	 	/s/
    Tony Chi Ming Chan
	 	Tony Chi Ming Chan

 

 

 

 

 

Signature Page to Insider Letter

 

    45

     

    

 

August 2, 2019

 

Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

 

Chardan Capital Markets,
LLC

17 State Street, Suite 1600

New York, NY 10004

 

		Re:	Initial Public Offering

 

Ladies and Gentlemen:

 

This letter is
being delivered to you in accordance with the Underwriting Agreement (the “Underwriting Agreement”) entered
into by and between Orisun Acquisition Corp., a Delaware corporation (the “Company”), and Chardan Capital
Markets, LLC, as Representative (the “Representative”) of the several underwriters named on Schedule
A thereto (the “Underwriters”), relating to an underwritten initial public offering (the “IPO”)
of the Company’s units (the “Units”), each comprised of one share of common stock of the Company,
par value $0.00001 per share (the “Common Stock”), one redeemable warrant, each warrant entitling its
holder to purchase one-half (1/2) of a share of Common Stock at an exercise price of $11.50 per full share (the “Warrants”),
and one right to receive one-tenth (1/10) of a share of Common Stock (the “Rights”). Certain capitalized
terms used herein are defined in paragraph 14 hereof.

 

In order to induce the
Company and the Underwriters to enter into the Underwriting Agreement and to proceed with the IPO, and in recognition of the benefit
that such IPO will confer upon the undersigned, and for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the undersigned hereby agrees with the Company as follows:

 

1. If the Company solicits
approval of its stockholders of a Business Combination, the undersigned will vote all shares of Common Stock beneficially owned
by him, her or it, whether acquired before, in or after the IPO, in favor of such Business Combination.

 

2. (a) Unless the Company’s
stockholders are previously given the option to redeem their shares in connection with amending applicable documents to extend
the time that the Company has to complete a Business Combination and that the Company fails to consummate a Business Combination
within 12 months from the closing of the Company’s IPO (or, in the event that the Company extended the period of time to
consummate a business combination up to three times, each by an additional three months, within 21 months) from the closing of
the Company’s IPO, the undersigned shall take all reasonable steps to (i) cause the Trust Fund to be liquidated and distributed
to the holders of the IPO Shares and (ii) cause the Company to liquidate as soon as reasonably practicable.

 

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(b) The undersigned
hereby waives any and all right, title, interest or claim of any kind in or to any distribution of the Trust Fund and any remaining
net assets of the Company as a result of such liquidation with respect to his, her or its Insider Shares (“Claim”)
and hereby waives any Claim the undersigned may have in the future as a result of, or arising out of, any contracts or agreements
with the Company and will not seek recourse against the Trust Fund for any reason whatsoever.

 

(c) In the event of
the liquidation of the Trust Fund, the undersigned agrees to indemnify and hold harmless the Company against any and all loss,
liability, claims, damage and expense whatsoever (including, but not limited to, any and all legal or other expenses reasonably
incurred in investigating, preparing or defending against any litigation, whether pending or threatened, or any claim whatsoever)
which the Company may become subject as a result of any claim by any vendor or other person who is owed money by the Company for
services rendered or products sold or contracted for, but only to the extent necessary to ensure that such loss, liability, claim,
damage or expense does not reduce the amount of funds in the Trust Fund; provided, that such indemnity shall not apply if such
vendor or other person has executed an agreement waiving any claims against the Trust Fund.

 

(d) In the event that
the Company does not consummate a Business Combination and must liquidate and its remaining net assets are insufficient to complete
such liquidation, the undersigned agrees to advance such funds necessary to complete such liquidation and agrees not to seek repayment
for such expenses.

 

3. In the event that
the Company does not consummate a Business Combination and must liquidate and its remaining net assets are insufficient to complete
such liquidation, the undersigned agrees to advance such funds necessary to complete such liquidation and agrees not to seek recourse
for such expenses.

 

4. The undersigned will
escrow all of his, her or its Insider Shares pursuant to the terms of a Stock Escrow Agreement, which the Company will enter into
with the undersigned and an escrow agent acceptable to the Company.

 

5. [Intentionally Omitted.]

 

6. In order to minimize
potential conflicts of interest which may arise from multiple affiliations, the undersigned agrees to present to the Company for
its consideration, prior to presentation to any other person or entity, any suitable opportunity to acquire a target business,
until the earlier of the consummation by the Company of a Business Combination or the liquidation of the Company, subject to any
pre-existing fiduciary and contractual obligations the undersigned might have.

 

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7. (a) The undersigned
acknowledges and agrees that prior to entering into a Business Combination with a target business that is affiliated with any Insiders
of the Company or their affiliates, including any company that is a portfolio company of, or otherwise affiliated with, or has
received financial investment from, an entity with which any Insider or their affiliates is affiliated, such transaction must be
approved by a majority of the Company’s disinterested independent directors and the Company must obtain an opinion from an
independent investment banking firm that such Business Combination is fair to the Company’s unaffiliated stockholders from
a financial point of view.

 

(b) The undersigned
hereby agrees and acknowledges that (i) each of the Underwriters and the Company may be irreparably injured in the event of a breach
of any of the obligations contained in this letter, (ii) monetary damages may not be an adequate remedy for such breach and (iii)
the non-breaching party shall be entitled to injunctive relief, in addition to any other remedy that such party may have in law
or in equity, in the event of such breach.

 

8. Neither the undersigned,
any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to receive and will not accept
any compensation or other cash payment prior to, or for services rendered in connection with, the consummation of the Business
Combination; provided that the Company shall be allowed to repay working capital loans made by the undersigned to the Company
in cash upon consummation of the Business Combination. Notwithstanding the foregoing, the undersigned and any affiliate of the
undersigned shall be entitled to reimbursement from the Company for their out-of-pocket expenses incurred in connection with identifying,
investigating and consummating a Business Combination.

 

9. Neither the undersigned,
any member of the family of the undersigned, nor any affiliate of the undersigned will be entitled to receive or accept a finder’s
fee or any other compensation in the event the undersigned, any member of the family of the undersigned or any affiliate of the
undersigned originates a Business Combination.

 

10. The undersigned agrees
to be a director/officer of the Company until the earlier of the consummation by the Company of a Business Combination or the liquidation
of the Company. The undersigned’s biographical information previously furnished to the Company and the Representative is
true and accurate in all material respects, does not omit any material information with respect to the undersigned’s biography
and contains all of the information required to be disclosed pursuant to Item 401 of Regulation S-K, promulgated under the Securities
Act of 1933. The undersigned’s FINRA Questionnaire previously furnished to the Company and the Representative is true and
accurate in all material respects. The undersigned represents and warrants that:

 

		(a)	He, she or it has never had a petition under the federal bankruptcy laws or any state insolvency law been filed by or against
(i) him, her or it, or any partnership in which he or she was a general partner at or within two years before the time of filing;
or (ii) any corporation or business association of which he or she was an executive officer at or within two years before the time
of such filing;

 

		(b)	He, she or it has never had a receiver, fiscal agent or similar officer been appointed by a court for his business or property,
or any such partnership;

 

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		(c)	He, she or it has never been convicted of fraud in a civil or criminal proceeding;

 

		(d)	He, she or it has never been convicted in a criminal proceeding or named the subject of a pending criminal proceeding (excluding
traffic violations and minor offenses);

 

		(e)	He, she or it has never been the subject of any order, judgment or decree, not subsequently reversed, suspended or vacated,
of any court of competent jurisdiction, permanently or temporarily enjoining or otherwise limiting him, her or it from (i) acting
as a futures commission merchant, introducing broker, commodity trading advisor, commodity pool operator, floor broker, leverage
transaction merchant, any other person regulated by the Commodity Futures Trading Commission (“CFTC”) or an associated
person of any of the foregoing, or as an investment adviser, underwriter, broker or dealer in securities, or as an affiliated person,
director or employee of any investment company, bank, savings and loan association or insurance company, or from engaging in or
continuing any conduct or practice in connection with any such activity; or (ii) engaging in any type of business practice;
or (iii) engaging in any activity in connection with the purchase or sale of any security or commodity or in connection with
any violation of federal or state securities or federal commodities laws;

 

		(f)	He, she, or it has never been the subject of any order, judgment or decree, not subsequently reversed, suspended or vacated,
of any federal or state authority barring, suspending or otherwise limiting for more than 60 days his, her or its right to engage
in any activity described in 10(e)(i) above, or to be associated with persons engaged in any such activity;

 

		(g)	He, she, or it has never been found by a court of competent jurisdiction in a civil action or by the SEC to have violated any
federal or state securities law, where the judgment in such civil action or finding by the SEC has not been subsequently reversed,
suspended or vacated;

 

		(h)	He, she, or it has never been found by a court of competent jurisdiction in a civil action or by the CFTC to have violated
any federal commodities law, where the judgment in such civil action or finding by the CFTC has not been subsequently reversed,
suspended or vacated;

 

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		(i)	He, she, or it has never been the subject of, or a party to, any Federal, State or foreign judicial or administrative order,
judgment, decree or finding, not subsequently reversed, suspended or vacated, relating to an alleged violation of (i) any Federal,
State or foreign securities or commodities law or regulation, (ii) any law or regulation respecting financial institutions or insurance
companies including, but not limited to, a temporary or permanent injunction, order of disgorgement or restitution, civil money
penalty or temporary or permanent cease-and desist order, or removal or prohibition order or (iii) any law or regulation prohibiting
mail or wire fraud or fraud in connection with any business entity;

 

		(j)	He, she or it has never been the subject of, or party to, any sanction or order, not subsequently reversed, suspended or vacated,
or any self-regulatory organization, any registered entity, or any equivalent exchange, association, entity or organization that
has disciplinary authority over its members or persons associated with a member;

 

		(k)	He, she or it has never been convicted of any felony or misdemeanor: (i) in connection with the purchase or sale of any security;
(ii) involving the making of any false filing with the SEC; or (iii) arising out of the conduct of the business of an underwriter,
broker, dealer, municipal securities dealer, investment advisor or paid solicitor of purchasers of securities;

 

		(l)	He, she or it was never subject to a final order of a state or foreign securities commission (or an agency of officer of a
state performing like functions); a state or foreign authority that supervises or examines banks, savings associations, or credit
unions; a state or foreign insurance commission (or an agency or officer of a state performing like functions); an appropriate
federal or foreign banking agency; the CFTC; or the National Credit Union Administration that is based on a violation of any law
or regulation that prohibits fraudulent, manipulative, or deceptive conduct;

 

		(m)	He, she or it has never been subject to any order, judgment or decree of any court of competent jurisdiction, that, at the
time of the sale of the Units, restrained or enjoined him, her or it from engaging or continuing to engage in any conduct or practice:
(i) in connection with the purchase or sale of any security; (ii) involving the making of any false filing with the SEC or any
foreign regulatory agency with similar functions; or (iii) arising out of the conduct of the business of an underwriter, broker,
dealer, municipal securities dealer, investment adviser or paid solicitor of purchasers of securities;

 

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		(n)	He, she or it has never been subject to any order of the SEC or any foreign regulatory agency with similar functions that orders
him, her or it to cease and desist from committing or causing a future violation of: (i) any scienter-based anti-fraud provision
of the federal securities laws, including, but not limited to, Section 17(a)(1) of the Securities Act, Section 10(b) of the Exchange
Act and Rule 10b-5 thereunder, Section 15(c) and Section 206(1) of the Advisers Act or any other rule or regulation thereunder;
or (ii) Section 5 of the Securities Act;

 

		(o)	He, she or it has never filed (as a registrant or issuer), or been named as an underwriter in any registration statement or
Regulation A offering statement filed with the SEC that was the subject of a refusal order, stop order, or order suspending the
Regulation A exemption, or is, currently, the subject of an investigation or proceeding to determine whether a stop order or suspension
order should be issued;

 

		(p)	He, she or it has never been subject to a United States Postal Service false representation order, or is currently subject
to a temporary restraining order or preliminary injunction with respect to conduct alleged by the United States Postal Service
to constitute a scheme or device for obtaining money or property through the mail by means of false representations;

 

		(q)	He, she or it is not subject to a final order of a state securities commission (or an agency of officer of a state performing
like functions); a state authority that supervises or examines banks, savings associations, or credit unions; a state insurance
commission (or an agency or officer of a state performing like functions); an appropriate federal banking agency; the CFTC; or
the National Credit Union Administration that bars the undersigned from: (i) association with an entity regulated by such commission,
authority, agency or officer; (ii) engaging in the business of securities, insurance or banking; or (iii) engaging in savings association
or credit union activities;

 

		(r)	He, she or it is not subject to an order of the SEC entered pursuant to section 15(b) or 15B(c) of the Securities Exchange
Act of 1934 (the “Exchange Act”) or section 203(e) or 203(f) of the Investment Advisers Act of 1940 (the “Advisers
Act”) that: (i) suspends or revokes the undersigned’s registration as a broker, dealer, municipal securities dealer
or investment adviser; (ii) places limitations on the activities, functions or operations of, or imposes civil money penalties
on, such person; or (iii) bars the undersigned from being associated with any entity or from participating in the offering of any
penny stock; and

 

		(s)	He, she or it has never been suspended or expelled from membership in, or suspended or barred from association with a member
of, a securities self-regulatory organization (e.g., a registered national securities exchange or a registered national or affiliated
securities association) for any act or omission to act constituting conduct inconsistent with just and equitable principles of
trade.

 

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11. The undersigned has
full right and power, without violating any agreement by which he, she or it is bound, to enter into this letter agreement and
to serve as a Director and/or officer of the Company.

 

12. The undersigned hereby
waives his, her or its right to exercise redemption rights with respect to any shares of Common Stock owned or to be owned by the
undersigned, directly or indirectly (or to sell such shares to the Company in a tender offer), whether purchased by the undersigned
prior to the IPO, in the IPO or in the aftermarket, and agrees that he, she or it will not seek redemption with respect to or otherwise
sell, such shares in connection with any vote to approve a Business Combination with respect thereto, a vote to amend the provisions
of the Company’s Amended and Restated Certificate of Incorporation, or a tender offer by the Company prior to a Business
Combination.

 

13. The undersigned hereby
agrees to not propose, or vote in favor of, an amendment to the Company’s Amended and Restated Certificate of Incorporation
with respect to the Company’s pre-Business Combination activities prior to the consummation of a Business Combination unless
the Company offers holders of IPO Shares the right to receive their pro rata portion of the funds then held in the Trust Fund.

 

14. In connection with
Section 5-1401 of the General Obligations Law of the State of New York, this letter agreement shall be governed by, and construed
in accordance with, the laws of the State of New York without regard to principles of conflicts of law that would result in the
application of the substantive law of another jurisdiction. The parties hereto agree that any action, proceeding or claim arising
out of or relating in any way to this letter agreement shall be resolved through final and binding arbitration in accordance with
the International Arbitration Rules of the American Arbitration Association (“AAA”). The arbitration shall be brought
before the AAA International Center for Dispute Resolution’s offices in New York City, New York, will be conducted in English
and will be decided by a panel of three arbitrators selected from the AAA Commercial Disputes Panel and that the arbitrator panel’s
decision shall be final and enforceable by any court having jurisdiction over the party from whom enforcement is sought. The cost
of such arbitrators and arbitration services, together with the prevailing party’s legal fees and expenses, shall be borne
by the non-prevailing party or as otherwise directed by the arbitrators.

 

15. As used herein, (i)
a “Business Combination” shall mean a merger, share exchange, asset acquisition, contractual arrangement,
share purchase, recapitalization, reorganization or other similar business combination with one or more businesses or entities;
(ii) “Insiders” shall mean all officers, directors and stockholders of the Company immediately prior
to the IPO; (iii) “Insider Shares” shall mean all of the shares of Common Stock of the Company acquired
by an Insider prior to the IPO and any shares of Common Stock underlying the Private Units; (iv) “IPO Shares”
shall mean the shares of Common Stock issued in the Company’s IPO; (v) [Intentionally Omitted;] (vi) “Registration
Statement” means the registration statement on Form S-1 filed by the Company with respect to the IPO; and (vii) “Trust
Fund” shall mean the trust fund into which a portion of the net proceeds of the Company’s IPO will be deposited.

 

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16. Any notice, consent
or request to be given in connection with any of the terms or provisions of this letter agreement shall be in writing and shall
be sent by express mail or similar private courier service, by certified mail (return receipt requested), by hand delivery or facsimile
transmission.

 

If to the Representative:

 

Chardan Capital Markets, LLC

17 State Street, Suite 1600

New York, NY 10004

Attn: George Kaufman

Facsimile: (646) 465-9039

 

with a copy (which copy shall not constitute
notice) to:

 

Ellenoff Grossman & Schole LLP 

1345 Avenue of the Americas

New York, New York 10105

Attn: Stuart Neuhauser, Esq. and Ari Edelman, Esq.

Facsimile.: (212) 370-7889

 

If to the Company:

 

Orisun Acquisition Corp.

555 Madison Avenue, Room 543

New York, NY 10022

Attn: Wei Chen, Chief Executive Officer

 

with a copy (which copy shall not constitute
notice) to:

 

Loeb & Loeb LLP

345 Park Avenue

New York, NY 10154

Attn: Giovanni Caruso, Esq.

Facsimile: (212) 504-3013

 

17. No party hereto may
assign either this letter agreement or any of its rights, interests, or obligations hereunder without the prior written consent
of the other party. Any purported assignment in violation of this paragraph shall be void and ineffectual and shall not operate
to transfer or assign any interest or title to the purported assignee. This letter agreement shall be binding on the parties hereto
and any successors and assigns thereof.

 

18. This Letter Agreement
constitutes the entire agreement and understanding of the parties hereto in respect of the subject matter hereof and supersedes
all prior understandings, agreements, or representations by or among the parties hereto, written or oral, to the extent they relate
in any way to the subject matter hereof or the transactions contemplated hereby. This Letter Agreement may not be changed, amended,
modified or waived (other than to correct a typographical error) as to any particular provision, except by a written instrument
executed by all parties hereto.

 

19. The undersigned acknowledges
and understands that the Underwriters and the Company will rely upon the agreements, representations and warranties set forth herein
in proceeding with the IPO. Nothing contained herein shall be deemed to render the Underwriters a representative of, or a fiduciary
with respect to, the Company, its stockholders or any creditor or vendor of the Company with respect to the subject matter hereof.

 

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	 	/s/ Wei
    Chen
	 	Wei Chen 

 

 

 

 

 

Signature Page to Insider Letter

 

 

54

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