EXHIBIT 4.6

DESCRIPTION OF CAPITAL STOCK

Our amended and restated certificate of incorporation provides that our authorized capital stock consists of 260,000,000 shares of common stock, $0.001 par value, and 5,000,000 shares of preferred stock, $0.01 par value. The following description of our capital stock and provisions of our amended and restated certificate of incorporation and amended and restated bylaws are only summaries, and we encourage you to review complete copies of our amended and restated certificate of incorporation and amended and restated bylaws, which we have previously filed with the SEC.

Common stock

Subject to the rights specifically granted to holders of any then outstanding shares of our preferred stock, our common stockholders are entitled to vote together as a class on all matters submitted to a vote of our stockholders and are entitled to any dividends that may be declared by our board of directors. Our common stockholders do not have cumulative voting rights. Upon our dissolution, liquidation or winding up, holders of our common stock are entitled to share ratably in our net assets after payment or provision for all liabilities and any preferential liquidation rights of our preferred stock then outstanding. Our common stockholders have no preemptive rights to purchase shares of our common stock. The issued and outstanding shares of our common stock are not subject to any redemption provisions and are not convertible into any other shares of our capital stock. All outstanding shares of our common stock are, and the shares of common stock to be issued in this offering will be, upon payment therefor, fully paid and non-assessable. The rights, preferences and privileges of holders of our common stock are subject to those of the holders of our Series A preferred stock, described below, and any other shares of our preferred stock we may issue in the future.

Anti-takeover considerations and special provisions of Delaware law, our certificate of incorporation and our bylaws

Delaware anti-takeover law

We are subject to the provisions of Section 203 of the Delaware General Corporation Law regulating corporate takeovers. This section prevents Delaware corporations, under certain circumstances, from engaging in a “business combination” with:

for three years following the date that the stockholder became an interested stockholder. A “business combination” includes a merger or sale of more than 10% of our assets.

However, the above provisions of Section 203 do not apply if:

This statute could prohibit or delay mergers or other change in control attempts, and thus may discourage attempts to acquire us.

Certificate of incorporation and bylaws

A number of provisions of our certificate of incorporation and bylaws concern matters of corporate governance and the rights of our stockholders. Provisions that grant our board of directors the ability to issue shares of preferred stock and to set the voting rights, preferences and other terms thereof may discourage takeover attempts that are not first approved by our board of directors, including takeovers which may be considered by some stockholders to be in their best interests. Certain provisions could delay or impede the removal of incumbent directors or the assumption of control by stockholders, even if such removal or assumption would be beneficial to our stockholders. These provisions also could discourage or make more difficult a merger, tender offer or proxy contest, even if they could be favorable to the interests of stockholders, and could potentially depress the market price of our common stock. Our board of directors believes that these provisions are appropriate to protect our interests and the interests of our stockholders.

Meetings of stockholders. Our bylaws provide that annual meetings of our stockholders may take place at the time and place established by our board of directors. A special meeting of our stockholders may be called at any time by the board or by any officer instructed by the directors to call the meeting.

Filling of board vacancies. Vacancies and newly created directorships resulting from any increase in the authorized number of directors may be filled by the affirmative vote of a majority of our directors then in office.

Amendment of the bylaws. Our bylaws may be amended or repealed by our board of directors or our stockholders.

Transfer agent, warrant agent and registrar

Continental Stock Transfer & Trust Company is the transfer agent and registrar for our common stock.