Exhibit 4.3



DESCRIPTION OF REGISTRANT’S SECURITIES
REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934



The following description of our capital
stock is intended as a summary only and therefore is not a complete description of our capital stock. This description is based
upon, and is qualified by reference to, our amended and restated certificate of incorporation (the “Amended Certificate”),
our amended and restated bylaws (the “Amended Bylaws”) and applicable provisions of Delaware corporate law. You should
read our Amended Certificate and Amended Bylaws, which are filed as exhibits to our Annual Report on Form 10-K, to which
this exhibit is also appended.



Our authorized capital stock consists of
35,000,000 shares of common stock, par value $0.0001 per share, and 2,000,000 shares of preferred stock, par value $0.0001 per
share.



Our common stock is the only class of securities
registered under Section 12 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”).



Common
Stock



Holders of our
common stock are entitled to one vote for each share held on all matters submitted to a vote of stockholders and do not have cumulative
voting rights. An election of directors by our stockholders shall be determined by a plurality of the votes cast by the stockholders
entitled to vote in the election. Subject to the supermajority votes for some matters, other matters shall be decided by the affirmative
vote of our stockholders having a majority in voting power of the votes cast by the stockholders present or represented and voting
on such matter. Holders of common stock are entitled to receive proportionately any dividends as may be declared by our board of
directors, subject to any preferential dividend rights of any series of preferred stock that we may designate and issue in the
future.



In the event of
our liquidation or dissolution, the holders of common stock are entitled to receive on a pro rata basis our net assets available
for distribution to stockholders after the payment of all debts and other liabilities, subject to the prior rights of any holders
of outstanding preferred stock. Holders of common stock have no preemptive, subscription, redemption or conversion rights. Our
outstanding shares of common stock are validly issued, fully paid and nonassessable. The rights, preferences and privileges of
holders of common stock are subject to and may be adversely affected by the rights of the holders of shares of any series of preferred
stock that we may designate and issue in the future.



Preferred
Stock



Under the terms
of our Amended Certificate our board of directors is authorized to direct us to issue shares of preferred stock in one or more
series without stockholder approval. Our board of directors has the discretion to determine the rights, preferences, privileges
and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences,
of each series of preferred stock.



The purpose of
authorizing our board of directors to issue preferred stock and determine its rights and preferences is to eliminate delays associated
with a stockholder vote on specific issuances. The issuance of preferred stock, while providing flexibility in connection with
possible acquisitions, future financings and other corporate purposes, could have the effect of making it more difficult for a
third party to acquire, or could discourage a third party from seeking to acquire, a majority of our outstanding voting stock.













Registration
Rights



Under our registration
rights agreement dated as of December 19, 2014, holders of 2,273,847 shares of common stock, or their transferees, have the
right to require us to register their shares under the Securities Act of 1933, as amended (the “Securities Act”) so
that those shares may be publicly resold, or to include their shares in any registration statement we file, in each case as further
described below.



Demand
Registration Rights



If holders of more
than 50% of the registrable securities request us to file a registration statement under the Securities Act for a public offering
of such shares of registrable securities having an aggregate offering price of at least $10,000,000, we must, within ten days after
the receipt of such notice, notify all holders of registrable securities of such request and shall use its reasonably diligent
efforts to register under the Securities Act the registrable securities of all holders who so request within 90 days after
the date of our notice; provided, however, that we are obligated to register only shares of common stock pursuant to the agreement.
We are obligated to effect a maximum of two such demand registrations.



Piggyback/Incidental
Registration Rights



Whenever we propose
to register any common stock for our own or others’ account under the Securities Act for a public offering for cash, other
than a registration relating to employee benefit plans, we must give each holder of registrable securities prompt written notice
of its intent to do so. Upon the written request of any such holder given within 10 days after receipt of such notice, we
will cause to be included in such registration all of the registrable securities that such holder requests; provided, however,
that we are obligated to register only shares of our common stock pursuant to the agreement. If we are advised in writing by any
managing underwriter of the securities being offered pursuant to any registration statement that the number of shares to be sold
by persons other than us is greater than the number of such shares that can be offered without adversely affecting the offering,
we may reduce pro rata the number of shares of registrable securities offered for the accounts of such persons to a number deemed
satisfactory by such managing underwriter; and a managing underwriter will have the right to exclude registrable securities entirely
pursuant to the preceding clause.



Form S-3
Registration Rights



If, at a time when
Form S-3 (or any successor thereto) is available for such registration, we receive from holders of more than 15% of the registrable
securities a written request or requests that we effect a registration on Form S-3 of registrable securities having an aggregate
offering price of at least $5,000,000 (based on the then current public market price), we will promptly give written notice of
the proposed registration to all other holders of registrable securities and, as soon as reasonably practicable, effect such registration
and all such related qualifications and compliances as may be requested and as would permit the sale and distribution of all registrable
securities as are specified in such request and any written requests of other holders given within 10 days after receipt of
such notice; provided, however, that the Company shall not be obligated to effect any such registration pursuant to the agreement:
(i) if Form S-3 is not available for such offering by the applicable holders; or (ii) if we furnish to the applicable
holders a certificate signed by the chief executive officer stating that in the good faith judgment of the board of directors,
it would be seriously detrimental to us and our stockholders for such Form S-3 registration to be effected at such time, in
which event we will have the right to defer the filing of the Form S-3 registration statement for a period of not more than
120 days after receipt of the request of the holder or holders; provided, however, that we may not utilize this right more
than twice in any 12-month period. We are not obligated to file more than two registrations under this provision.



Other
Provisions and Expenses



A registrable security
will cease to be a registrable security when (i) a registration statement covering such registrable security has been declared
effective by the SEC and it has been disposed of pursuant to such effective registration statement; or (ii) such registrable
security could be sold pursuant to Rule 144 (or any successor or comparable provision) without any volume restriction.





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Other than underwriting
discounts and commissions and certain other expenses, we will be required to pay all expenses incurred by us related to any registration
effected pursuant to the exercise of these registration rights. These expenses may include all registration and filing fees, printing
expenses, fees and disbursements of our counsel, reasonable fees and disbursements of a counsel for the selling stockholders and
blue sky fees and expenses.



Warrant
to Purchase Common Stock



In connection with the initial public offering
of our common stock (the “IPO”), we issued to ThinkEquity, a division of Fordham Financial Management, Inc. (the “Representative”),
a warrant (the “Representative’s Warrants”) to purchase 100,000 shares of our common stock at an exercise price
of $7.50 per share (125% of our IPO price per share). The exercise price and number of shares issuable upon exercise of the warrants
may be adjusted in certain circumstances including in the event of a stock dividend or our recapitalization, reorganization, merger
or consolidation. However, the warrant exercise price or underlying shares will not be adjusted for issuances of shares of common
stock at a price below the warrant exercise price. The Warrant is exercisable at any time, from time to time, in whole or in part,
during the four-year period commencing one year from the effective date of the registration statement related to this offering.



The Representative’s Warrants and
the shares of common stock underlying the Representative’s Warrants have been deemed compensation by FINRA and are, therefore,
subject to a 180-day lock-up pursuant to FINRA Rule 5110(g)(1). The Representative or permitted assignees under such rule may not
sell, transfer, assign, pledge, or hypothecate the Representative’s Warrants or the securities underlying the Representative's
Warrants, nor will the representative engage in any hedging, short sale, derivative, put, or call transaction that would result
in the effective economic disposition of the Representative's Warrants or the underlying shares of common stock for a period of
180 days from January 28, 2020. Additionally, the Representative's Warrants may not be sold, transferred, assigned, pledged, or
hypothecated for a 180-day period following January 28, 2020, except to any underwriter and selected dealer participating in the
offering and their bona fide officers or partners. The Representative's Warrants provide for registration rights upon request,
in certain cases. The demand registration right provided will not be greater than five years from the effective date of this registration
statement in compliance with FINRA Rule 5110(f)(2)(G)(iv). The piggyback registration right provided will not be greater than seven
years from the effective date of this registration statement in compliance with FINRA Rule 5110(f)(2)(G)(v). We will bear all fees
and expenses attendant to registering the securities issuable on exercise of the Representative’s Warrants other than underwriting
commissions incurred and payable by the holders.



Anti-Takeover
Effects of Delaware Law and Our Amended Certificate and Amended Bylaws



Some provisions
of Delaware law, our Amended Certificate and Amended Bylaws could make the following transactions more difficult: an acquisition
of us by means of a tender offer; an acquisition of us by means of a proxy contest or otherwise; or the removal of our incumbent
officers and directors. It is possible that these provisions could make it more difficult to accomplish or could deter transactions
that stockholders may otherwise consider to be in their best interest or in our best interests, including transactions which provide
for payment of a premium over the market price for our shares.



These provisions,
summarized below, are intended to discourage coercive takeover practices and inadequate takeover bids. These provisions are also
designed to encourage persons seeking to acquire control of us to first negotiate with our board of directors. We believe that
the benefits of the increased protection of our potential ability to negotiate with the proponent of an unfriendly or unsolicited
proposal to acquire or restructure us outweigh the disadvantages of discouraging these proposals because negotiation of these proposals
could result in an improvement of their terms.



Authorized
but Unissued Shares



Our authorized
but unissued shares of common stock and preferred stock are available for future issuance without stockholder approval. These additional
shares may be utilized for a variety of corporate purposes, including future public offerings to raise additional capital and corporate
acquisitions. The existence of authorized but unissued shares of common stock and preferred stock could render more difficult or
discourage an attempt to obtain control of a majority of our common stock by means of a proxy contest, tender offer, merger or
otherwise.





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Stockholder
Meetings



Any action to be
taken by our stockholders must be effected at a duly called annual or special meeting of stockholders and not be taken by written
consent.



Requirements
for Advance Notification of Stockholder Nominations and Proposals



Stockholders seeking
to present proposals before a meeting of stockholders or to nominate candidates for election as directors at a meeting of stockholders
must provide advance notice in writing, and also specify requirements as to the form and content of a stockholder's notice.



Delaware
Anti-Takeover Statute



We are subject
to Section 203 of the General Corporation Law of the State of Delaware, which prohibits persons deemed to be “interested
stockholders” from engaging in a “business combination” with a publicly held Delaware corporation for three years
following the date these persons become interested stockholders unless the business combination is, or the transaction in which
the person became an interested stockholder was, approved in a prescribed manner or another prescribed exception applies. Generally,
an “interested stockholder” is a person who, together with affiliates and associates, owns, or within three years prior
to the determination of interested stockholder status did own, 15% or more of a corporation's voting stock. Generally, a “business
combination” includes a merger, asset or stock sale, or other transaction resulting in a financial benefit to the interested
stockholder. The existence of this provision may have an anti-takeover effect with respect to transactions not approved in advance
by the board of directors.



Choice
of Forum



The Court of Chancery
of the State of Delaware is the exclusive forum in which we and our directors may be sued by our stockholders, to the fullest extent
permitted by law, 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, our Amended Certificate,
or our Amended Bylaws; or
| | - | ----------------------------------------------------------------------------------------------------------------------------------------------------

| | · | any action asserting a claim against us that is governed by the internal affairs doctrine.
| | - | ------------------------------------------------------------------------------------------



Our Amended Bylaws
do not apply to suits brought to enforce a duty or liability created by the Securities Act or the Exchange Act, or any other claim
for which federal courts have exclusive jurisdiction.



These choice of
forum provisions may limit a stockholder's ability to bring a claim in a judicial forum that it finds favorable for disputes with
us or any of our directors, officers, or other employees, which may discourage lawsuits with respect to such claims. Alternatively,
if a court were to find either choice of forum provision contained in our Amended Bylaws to be inapplicable or unenforceable in
an action, we may incur additional costs associated with resolving such action in other jurisdictions, which could harm our business,
results of operations, and financial condition.





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Advance
Notice Requirements



Our Amended Bylaws
establish an advance notice procedure for stockholder proposals to be brought before an annual meeting of our stockholders, including
proposed nominations of persons for election to the board of directors. Stockholders at an annual meeting will only be able to
consider proposals or nominations specified in the notice of meeting or brought before the meeting by or at the direction of the
board of directors or by a stockholder who was a stockholder of record on the record date for the meeting, who is entitled to vote
at the meeting and who has given our Secretary timely written notice, in proper form, of the stockholder's intention to bring that
business before the meeting. Although our Amended Bylaws do not give the board of directors the power to approve or disapprove
stockholder nominations of candidates or proposals regarding other business to be conducted at a special or annual meeting, our
Amended Bylaws may have the effect of precluding the conduct of certain business at a meeting if the proper procedures are not
followed or may discourage or deter a potential acquirer from conducting a solicitation of proxies to elect its own slate of directors
or otherwise attempting to obtain control of us.



Transfer Agent and Registrar



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



National Securities Exchange Listing



Our common stock listed on NYSE American
under the symbol “ANVS.”





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