Exhibit 4.20

       

      

      CHF Solutions, Inc.

       

      Description of Securities

       

      General

       

      CHF Solutions, Inc. is incorporated in the State of Delaware.  The following description summarizes the most important terms of our capital stock. This description is not
          complete, and we qualify it by referring to our certificate of incorporation, bylaws and certificate of designation of preferences, rights and limitations of Series F Preferred Stock, copies of which have
          been incorporated by reference as exhibits to the Annual Report on Form 10-K of which this exhibit is a part, and to the applicable provisions of the Delaware General Corporation Law.

       

      Common Stock

       

      Dividends

       

      Holders of our common stock are entitled to receive dividends when and as declared by our board of directors out of funds legally available.

       

      Voting

       

      Holders of our common stock are entitled to one vote for each share on each matter properly submitted to our stockholders for their vote; provided however, that except as otherwise required by law, holders of our common
        stock will not be entitled to vote on any amendment to our certificate of incorporation (including any certificate of designation filed with respect to any series of preferred stock) that relates solely to the terms of a series of outstanding
        preferred stock if the holders of such affected series are entitled, either separately or together as a class with the holders of one or more other such series, to vote thereon by law or pursuant to our certificate of incorporation (including any
        certificate of designation filed with respect to any series of preferred stock).

       

      Subject to the voting restrictions described above, holders of our common stock may adopt, amend or repeal our bylaws and/or alter certain provisions of our certificate of incorporation with the affirmative vote of the
        holders of at least 66 2 ∕ 3 % of the voting power of all of the then-outstanding shares of our capital stock entitled to vote generally in the election of directors,
        voting together as a single class, in addition to any vote of the holders of a class or series of our stock required by law or our certificate of incorporation. Those provisions of our certificate of incorporation that may be altered only by the
        super-majority vote described above relate to:

       

      
        
          
            
              
                
                  
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                             the number of directors on our
                                board of directors, the classification of our board of directors and the terms of the members of our board of directors;

                          


                  

                

              

            

          

        

      

       

      
        
          
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                    the limitations on removal of any of our directors described below under
                        “—Anti-Takeover Effects of Certain Provisions of Our Certificate of Incorporation and Bylaws and Delaware Law;”

                  


          

        

      

       

      
        
          
            	 	
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                    the ability of our directors to fill any vacancy on our board of directors by the affirmative vote of a majority of the
                        directors then in office under certain circumstances;

                  


          

        

      

       

      
        	 	
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                the ability of our board of directors to adopt, amend or repeal our bylaws and the
                    super-majority vote of our stockholders required to adopt, amend or repeal our bylaws described above;

              


      

       

      
        	 	
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                the limitation on action of our stockholders by written action described below under “—Anti-Takeover Effects of Certain Provisions
                    of Our Certificate of Incorporation and Bylaws and Delaware Law;”

              


      

       

      
        	 	
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                the choice of forum provision described below under “—Choice of Forum;”

              


      

       

      
        	 	
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                the limitations on director liability and indemnification described below under the heading “—Limitation on Liability of Directors
                    and Indemnification;” and

              


      

      

      
        

        
          


      

      
        	 	
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                the super-majority voting requirement to amend our certificate of incorporation described above.

              


      

      

      Conversion, Redemption and Preemptive Rights

      

      Holders of our common stock do not have any conversion, redemption or preemptive rights pursuant to our organizational documents.

       

      Liquidation, Dissolution and Winding-up

       

      In the event of our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in any assets remaining after the satisfaction in full of the prior rights of creditors and the
        aggregate of any liquidation preference pursuant to the terms of any certificate of designation filed with respect to any series of preferred stock, including our outstanding Series F Preferred Stock.

      

      Preferred Stock

      

      We may issue any class of preferred stock in any series. Our board of directors has the authority to establish and designate series, and to fix the number of shares included in each such series and to determine or alter
        for each such series, such voting powers, designation, preferences, and relative participating, optional, or other rights and such qualifications, limitations or restrictions thereof. Our board of directors is not restricted in repurchasing or
        redeeming such stock while there is any arrearage in the payment of dividends or sinking fund installments. Our board of directors is authorized to increase or decrease the number of shares of any series subsequent to the issuance of shares of that
        series, but not below the number of shares of such series then outstanding. The number of authorized shares of preferred stock may be increased or decreased, but not below the number of shares thereof then outstanding, by the affirmative vote of
        the holders of a majority of the common stock, without a vote of the holders of the preferred stock, or of any series thereof, unless a vote of any such holders is required pursuant to the terms of any certificate of designation filed with respect
        to any series of preferred stock.

       

      Prior to issuance of shares of any series of preferred stock, our board of directors is required by Delaware law to adopt resolutions and file a certificate of designation with the Secretary of State of the State of
        Delaware. The certificate of designation fixes for each class or series the terms, preferences, conversion or other rights, voting powers, restrictions, limitations as to dividends or other distributions, qualifications and terms or conditions of
        redemption for each class or series. Any shares of preferred stock will, when issued, be fully paid and non-assessable.

       

      Series F Convertible Preferred Stock.

       

      Our board of directors designated 18,000 shares of preferred stock as Series F convertible preferred stock, $0.0001 par value (“Series F Preferred Stock”).

       

      Liquidation. Upon any dissolution, liquidation or winding up, whether voluntary or involuntary, holders of Series F Preferred Stock will be entitled to receive distributions out of
        our assets, whether capital or surplus, of an amount equal to $0.0001 per share of Series F Preferred Stock before any distributions shall be made on the common stock or any series of preferred stock ranked junior to the Series F Preferred Stock.

       

      Dividends. Holders of the Series F Preferred Stock are entitled to receive dividends equal (on an “as converted to common stock” basis) to and in the same form as dividends
        actually paid on shares of our common stock when, as and if such dividends are paid on shares of our common stock. No other dividends will be paid on shares of Series F Preferred Stock.

       

      Conversion. Each share of Series F Preferred Stock is convertible, at any time and from time to time at the option of the holder thereof, into that number of shares of common stock
        determined by dividing $1,000 by the then-current conversion price (subject to adjustment described below).  As of December 31, 2020, the conversion price was $9.00. This right to convert is limited by the beneficial ownership limitation described
        below.

       

      Forced Conversion. Subject to certain ownership limitations as described below and certain equity conditions being met, until such time that during any 20 of 30 consecutive trading
        days, the volume weighted average price of our common stock exceeds 300% of the conversion price and the daily dollar trading volume during such period exceeds $200,000 per trading day, we have the right to force the conversion of the Series F
        Preferred Stock into common stock.

       

      

      
        

        
          


        

      

      Beneficial Ownership Limitation. A holder shall have no right to convert any portion of Series F Preferred Stock, to the extent that, after giving effect to such conversion, such
        holder, together with such holder’s affiliates, and any persons acting as a group together with such holder or any such affiliate, would beneficially own in excess of 4.99% of the number of shares of common stock outstanding immediately after
        giving effect to the issuance of shares of common stock upon such conversion (subject to the right of the holder to increase such beneficial ownership limitation upon not less than 61 days prior notice provided that such limitation can never exceed
        9.99% and such 61 day period cannot be waived). Beneficial ownership of the holder and its affiliates will be determined in accordance with Section 13(d) of the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated
        thereunder. Holders of Series F Preferred Stock who are subject to such beneficial ownership limitation are and will remain responsible for ensuring their own compliance with Regulation 13D-G promulgated under the Securities Exchange Act of 1934,
        as amended, consistent with their individual facts and circumstances. In addition, pursuant to Rule 13d-3(d)(1) (i) promulgated under the Securities Exchange Act of 1934, as amended, any person who acquires Series F Preferred Stock with the purpose
        or effect of changing or influencing the control of our company, or in connection with or as a participant in any transaction having such purpose or effect, immediately upon such acquisition will be deemed to be the beneficial owner of the
        underlying common stock.

       

      Optional Redemption. Subject to the terms of the certificate of designation, the Company holds an option to redeem some or all the Series F Preferred Stock six months after its
        issuance date at a 200% premium to the stated value of the Series F Preferred Stock subject to the redemption, upon 30 days prior written notice to the holder of the Series F Preferred Stock. The Series F Preferred Stock would be redeemed by the
        Company for cash.

       

      Conversion Price Adjustment

       

      Subsequent Equity Sales. The Series F Preferred Stock has full ratchet price based anti-dilution protection, subject to customary carve outs, in the event of a down-round financing
        at a price per share below the conversion price of the Series F Preferred Stock. If during any 20 of 30 consecutive trading days the volume weighted average price of our common stock exceeds 300% of the then-effective conversion price of the Series
        F Preferred Stock and the daily dollar trading volume for each trading day during such period exceeds $200,000, the anti-dilution protection in the Series F Preferred Stock will expire and cease to apply.

       

      Stock Dividends and Stock Splits. If we pay a stock dividend or otherwise make a distribution payable in shares of common stock on shares of common stock or any other common stock
        equivalents, subdivide or combine outstanding common stock, or reclassify common stock, the conversion price will be adjusted by multiplying the then conversion price by a fraction, the numerator of which shall be the number of shares of common
        stock outstanding immediately before such event, and the denominator of which shall be the number of shares outstanding immediately after such event.

       

      Fundamental Transaction. If we effect a fundamental transaction in which we are the surviving entity, then upon any subsequent conversion of Series F Preferred Stock, the holder
        thereof shall have the right to receive, for each share of common stock that would have been issuable upon such conversion immediately prior to the occurrence of such fundamental transaction, the number of shares of our common stock and any
        additional consideration receivable as a result of such fundamental transaction by a holder of the number of shares of common stock into which Series F Preferred Stock is convertible immediately prior to such fundamental transaction. If we effect a
        fundamental transaction in which we are not the surviving entity or a reverse merger in which we are the surviving entity, then the surviving entity shall purchase the outstanding Series F Preferred Stock by paying and issuing, in the event that
        such consideration given to common stockholders is non-cash consideration, as the case may be, to such holder (or canceling such holder’s outstanding Series F Preferred Stock and converting it into the right to receive) an amount equal to the
        greater of (i) the cash consideration plus the non-cash consideration (in the form issuable to the holders of common stock) per share of the common stock in the fundamental transaction multiplied by the number of conversion shares underlying the
        shares of Series F Preferred Stock held by the holder on the date of the consummation of the fundamental transaction or (ii) 130% of the stated value of the Series F Preferred Stock then outstanding on the date immediately prior to the consummation
        of the fundamental transaction. Such amount shall be paid in the same form and mix (be it securities, cash or property, or any combination of the foregoing) as the consideration received by the common stock in such fundamental transaction. A
        fundamental transaction means: (i) our merger or consolidation with or into another entity, (ii) any sale or other disposition of all or substantially all of our assets in one transaction or a series of related transactions, (iii) any tender offer
        or exchange offer allowing holders of our common stock to tender or exchange their shares for cash, property or securities, and has been accepted by the holders of 50% or more of the outstanding common stock (iv) any reclassification of our common
        stock or any compulsory share exchange by which common stock is effectively converted into or exchanged for other securities, cash or property, or (v) consummation of a stock or share purchase agreement or other business combination with another
        person whereby such other person acquires more than 50% of the outstanding shares of common stock.

       

      
        

        
          


        

      

      Voting Rights, etc. Except as otherwise provided in the Series F Preferred Stock certificate of designation or required by law, the Series F Preferred Stock has no voting rights.
        However, as long as any shares of Series F Preferred Stock are outstanding, we may not, without the affirmative vote of the holders of a majority of the then outstanding shares of the Series F Preferred Stock, alter or change adversely the powers,
        preferences or rights given to the Series F Preferred Stock, amend its certificate of designation, amend our certificate of incorporation or other charter documents in any manner that adversely affects any rights of the holders, increase the number
        of authorized shares of Series F Preferred Stock, or enter into any agreement with respect to any of the foregoing. The Series F Preferred Stock certificate of designation provides that if any party commences an action or proceeding to enforce any
        provisions of the certificate of designation, then the prevailing party in such action or proceeding shall be reimbursed by the other party for its attorneys’ fees and other costs and expenses incurred in the investigation, preparation and
        prosecution of such action or proceeding. This provision may, under certain circumstances, be inconsistent with federal securities laws and Delaware general corporation law.

       

      Fractional Shares. No fractional shares of common stock will be issued upon conversion of Series F Preferred Stock. Rather, we shall, at our election, either pay a cash adjustment
        in respect of such final fraction in an amount equal to such fraction multiplied by the conversion price or round up to the next whole share.

       

      The Series F Preferred Stock was issued in book-entry form under a preferred stock agent agreement between American Stock Transfer & Trust as preferred stock agent, and us, and shall initially be represented by one or
        more book-entry certificates deposited with The Depository Trust Company, or DTC, and registered in the name of Cede & Co., a nominee of DTC, or as otherwise directed by DTC. There is no established public trading market for the Series F
        Preferred Stock, and the Series F Preferred Stock is not listed on The Nasdaq Capital Market, any other national securities exchange or any other nationally recognized trading system.

       

      Description of Outstanding Warrants

      

      As of December 31, 2020, there were warrants outstanding to purchase a total of 1,631,948 shares of our common stock, which were exercisable at prices ranging from $9.00 to $53,550 and are exercisable over a period
        ranging from 10 months to 4.9 years. Certain of these warrants have a net exercise provision under which its holder may, in lieu of payment of the exercise price in cash, surrender the warrant and receive a net amount of shares based on the fair
        market value of our common stock at the time of exercise of the warrant after deduction of the aggregate exercise price. Each of these warrants also contains provisions for the adjustment of the exercise price and the aggregate number of shares
        issuable upon the exercise of the warrant in the event of dividends, share splits, reorganizations and reclassifications and consolidations. Certain of these warrants provide that, subject to limited exceptions, a holder will not have the right to
        exercise any portion of its warrants if the holder, together with its affiliates, would beneficially own over 4.99% of our then outstanding common stock following such exercise; provided, however, that upon prior notice to us, the warrant holder
        may increase its ownership, provided that in no event will the ownership exceed 9.99%.

       

      Anti-Takeover Effects of Certain Provisions of Our Certificate of Incorporation and Bylaws and Delaware Law

       

      Certificate of Incorporation and Bylaws

       

      Certain provisions of our certificate of incorporation and bylaws may be considered to have an anti-takeover effect, such as those provisions:

       

      
        	 	
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                providing for our board of directors to be divided into three classes with staggered three-year terms, with only one class of
                    directors being elected at each annual meeting of our stockholders and the other classes continuing for the remainder of their respective three-year terms;

              


      

       

      
        	 	
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                authorizing our board of directors to issue from time to time any series of preferred stock and fix the voting powers, designation,
                    powers, preferences and rights of the shares of such series of preferred stock;

              


      

       

      
        	 	
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                prohibiting stockholders from acting by written consent in lieu of a meeting;

              


      

       

      
        	 	
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                requiring advance notice of stockholder intention to put forth director nominees or bring up other business at a stockholders’
                    meeting;

              


      

       

      
        	 	
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                prohibiting stockholders from calling a special meeting of stockholders;

              


      

       

        

      
        
          
            	 	
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                    requiring a 662∕3% super-majority stockholder approval in order for stockholders to alter, amend or repeal certain provisions of our
                        certificate of incorporation;

                  


          

        

      

      

      
        

        
          


        

      

      
        	 	
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                requiring a 662∕3% super-majority stockholder approval in order for stockholders to adopt, amend or repeal our bylaws;

              


      

       

      
        	 	
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                providing that, subject to the rights of the holders of any series of preferred stock to elect additional directors under specified
                    circumstances, neither the board of directors nor any individual director may be removed without cause;

              


      

       

      
        	 	
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                creating the possibility that our board of directors could prevent a coercive takeover of our Company due to the significant amount
                    of authorized, but unissued shares of our common stock and preferred stock;

              


      

       

      
        	 	
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                providing that, subject to the rights of the holders of any series of preferred stock, the number of directors shall be fixed from
                    time to time exclusively by our board of directors pursuant to a resolution adopted by a majority of the total number of authorized directors; and

              


      

       

      
        	 	
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                providing that any vacancies on our board of directors under certain circumstances will be filled only by a majority of our board
                    of directors then in office, even if less than a quorum, and not by the stockholders.

              


      

       

      Delaware Law

       

      We are also subject to Section 203 of the DGCL, which generally prohibits a Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years following the date
        that the stockholder became an interested stockholder, unless:

       

      
        	 	
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                prior to that date, our board of directors approved either the business combination or the transaction that resulted in the
                    stockholder becoming an interested stockholder;

              


      

       

      
        	 	
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                upon consummation of the transaction that resulted in the stockholder becoming an interested stockholder, the interested
                    stockholder owned at least 85% of our voting stock outstanding at the time the transaction commenced, excluding for purposes of determining the number of shares outstanding (but not the outstanding voting stock owned by the interested
                    stockholder) those shares owned by (i) persons who are directors and also officers and (ii) employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan
                    will be tendered in a tender or exchange offer; or

              


      

       

      
        	 	
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                on or subsequent to that date, the business combination is approved by our board of directors and authorized at an annual or
                    special meeting of stockholders, and not by written consent, by the affirmative vote of at least 66 2 ∕ 3 % of the outstanding voting stock that is not owned by the interested stockholder.

              


      

       

      In general, Section 203 of the DGCL defines an interested stockholder as an entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person affiliated with or
        controlling or controlled by any of these entities or persons.

       

      The above-summarized provisions of our certificate of incorporation and bylaws and the above-summarized provisions of the DGCL could make it more difficult to acquire us by means of a tender offer, a proxy contest or
        otherwise, or to remove incumbent officers and directors. These provisions are expected to discourage certain types of coercive takeover practices and takeover bids that our board of directors may consider inadequate and to encourage persons
        seeking to acquire control of us to first negotiate with our board of directors. We believe that the benefits of increased protection of our ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure
        us outweigh the disadvantages of discouraging takeover or acquisition proposals because, among other things, negotiation of these proposals could result in an improvement of their terms.

       

      Choice of Forum

       

      Our Fourth Amended and Restated Certificate of Incorporation, as amended, provides that, unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware will be the
        exclusive forum for any derivative action or proceeding brought on our behalf; any action asserting a breach of fiduciary duty; any action asserting a claim against us arising pursuant to the Delaware General Corporation Law; or any action
        asserting a claim against us that is governed by the internal affairs doctrine. These provisions would not apply to suits brought to enforce a duty or liability created by the Exchange Act, or any other claim for which the federal courts have
        exclusive jurisdiction. Our Fourth Amended and Restated Certificate of Incorporation, as amended, will further provide that the federal district courts of the United States of America will be the exclusive forum for resolving any complaint
        asserting a cause of action arising under the Securities Act, subject to applicable law. Any person or entity purchasing or otherwise acquiring any interest in our securities shall be deemed to have notice of and consented to these provisions. Our
        exclusive forum provision will not relieve us of our duties to comply with the federal securities laws and the rules and regulations thereunder, and our stockholders will not be deemed to have waived our compliance with these laws, rules and
        regulations.

       

      

      
        

        
          


        

      

      The provisions of the Delaware General Corporation Law, our Fourth Amended and Restated Certificate of Incorporation, as amended, and our Second Amended and Restated Bylaws could have the effect of discouraging others
        from attempting hostile takeovers and, as a consequence, they may also inhibit temporary fluctuations in the price of our common stock that often result from actual or rumored hostile takeover attempts. These provisions may also have the effect of
        preventing changes in our management. It is possible that these provisions could make it more difficult to accomplish transactions that stockholders may otherwise deem to be in their best interests.

       

      Limitation on Liability of Directors and Indemnification

       

      Our certificate of incorporation limits the liability of our directors to the fullest extent permitted by Delaware law. Delaware law provides that directors of a corporation will not be personally liable for monetary
        damages for breach of their fiduciary duties as directors, except for liability for any:

       

      
        	 	
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                breach of their duty of loyalty to us or our stockholders;

              


      

       

      
        	 	
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                act or omission not in good faith or that involves intentional misconduct or a knowing violation of law;

              


      

       

      
        	 	
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                unlawful payment of dividends or redemption of shares as provided in Section 174 of the DGCL; or

              


      

       

      
        	 	
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                transaction from which the directors derived an improper personal benefit.

              


      

       

      These limitations of liability do not apply to liabilities arising under federal securities laws and do not affect the availability of equitable remedies such as injunctive relief or rescission.

       

      Our bylaws provide that we will indemnify and advance expenses to our directors and officers to the fullest extent permitted by law or, if applicable, pursuant to indemnification agreements. They further provide that we
        may choose to indemnify our other employees or agents from time to time. Subject to certain exceptions and procedures, our bylaws also require us to advance to any person who was or is a party, or is threatened to be made a party, to any proceeding
        by reason of the person’s service as one of our directors or officers all expenses incurred by the person in connection with such proceeding.

       

      Section 145(g) of the DGCL and our bylaws also permit us to secure insurance on behalf of any officer, director, employee or other agent for any liability arising out of his or her actions in connection with their
        services to us, regardless of whether our bylaws permit indemnification. We maintain a directors’ and officers’ liability insurance policy.

       

      We entered into indemnification agreements with each of our directors and executive officers that provide, in general, that we will indemnify them to the fullest extent permitted by law in connection with their service to
        us or on our behalf and, subject to certain exceptions and procedures, that we will advance to them all expenses that they incur in connection with any proceeding to which they are, or are threatened to be made, a party.

       

      At present, there is no pending litigation or proceeding involving any of our directors or officers as to which indemnification is required or permitted, and we are not aware of any threatened litigation or proceeding
        that may result in a claim for indemnification.

       

      Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the Company pursuant to the foregoing provisions, or otherwise, the Company
        has been advised that in the opinion of the SEC this indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.

       

      Transfer Agent and Registrar

       

      The transfer agent and registrar for our common stock is American Stock Transfer & Trust Company LLC.

       

      Listing

       

      Our common stock trades on The Nasdaq Capital Market under the symbol “CHFS.”