Description of Capital Stock

Exhibit 4.5

DESCRIPTION OF CAPITAL STOCK

The following description of our capital stock does not purport to be complete and is subject to, and qualified in its entirety by, our amended and restated certificate of incorporation and amended and restated bylaws, which are incorporated by reference into this Description of Capital Stock, and by the Delaware General Corporation Law (the “DGCL”).

General Matters

Our certificate of incorporation, as amended, provides that we are authorized to issue 300,000,000 shares of common stock, par value $0.01 per share, and 10,000,000 shares of undesignated preferred stock, par value $0.01 per share.

Common Stock

Shares of our common stock have the following rights, preferences, and privileges:

Preferred Stock

Under our certificate of incorporation, without further stockholder action, the board of directors is authorized, subject to any limitations prescribed by the law of the State of Delaware, to provide for the issuance of the shares of preferred stock in one or more series, to establish from time to time the number of shares to be included in each such series, and to fix the designation, powers, preferences and rights of the shares of each such series and any qualifications, limitations or restrictions thereof.

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

Our certificate of incorporation and bylaws contain provisions that are intended to enhance the likelihood of continuity and stability in the composition of the board of directors and that may have the effect of delaying, deferring or preventing a future takeover or change in control of our company unless the takeover or change in control is approved by our board of directors. These provisions include the following:

Staggered board of directors. Our certificate of incorporation and bylaws provide for a staggered board of directors, divided into three classes, with our stockholders electing one class each year. Between stockholders’ meetings, the board of directors will be able to appoint new directors to fill vacancies or newly created directorships so that no more than the number of directors in any given class could be replaced each year and it would take three successive annual meetings to replace all directors.

Elimination of stockholder action through written consent. Our certificate of incorporation and bylaws provide that stockholder action can be taken only at an annual or special meeting of stockholders and cannot be taken by written consent in lieu of a meeting.

Elimination of the ability to call special meetings. Our certificate of incorporation and bylaws provide that, except as otherwise required by law, special meetings of our stockholders can only be called pursuant to a resolution adopted by a majority of our board of directors, a committee of the board of directors that has been duly designated by the board of directors and whose powers and authority include the power to call such meetings or by our chief executive officer or the chairman of our board of directors. Stockholders are not permitted to call a special meeting or to require our board to call a special meeting.

Advance notice procedures for stockholder proposals. Our 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 our board. Stockholders at our annual meeting may only consider proposals or nominations specified in the notice of meeting or brought before the meeting by or at the direction of our board 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 to our secretary timely written notice, in proper form, of the stockholder’s intention to bring that business before the meeting.

Removal of directors; board of directors vacancies. Our certificate of incorporation and bylaws provide that members of our board of directors may not be removed without cause and the affirmative vote of holders of at least a majority of the voting power of our then-outstanding capital stock entitled to vote on the election of directors. Our bylaws further provide that only our board of directors may fill vacant directorships, except in limited circumstances. These provisions would prevent a stockholder from gaining control of our board of directors by removing incumbent directors and filling the resulting vacancies with such stockholder’s own nominees.

Amendment of certificate of incorporation and bylaws. The DGCL provides generally that the affirmative vote of a majority of the outstanding shares entitled to vote is required to amend or repeal a corporation’s certificate of incorporation or bylaws, unless the certificate of incorporation requires a greater percentage. Our certificate of incorporation requires the approval of the holders of at least two-thirds of the voting power of the issued and outstanding shares of our capital stock entitled to vote in connection with the election of directors to amend certain provisions of our certificate of incorporation relating to the directors, including their authority to amend our by-laws, the size of our board of directors,

provision for a staggered board of directors, the removal of directors, and vacancies on the board of directors, as well as our authority to provide indemnification for our directors and officers. Our bylaws provide that a majority of our board of directors or, in most cases, the holders of at least a majority of the voting power of the issued and outstanding shares of our capital stock entitled to vote thereon have the power to amend or repeal our bylaws, except that, in the case of amendments or repeals approved by stockholders, the affirmative vote of holders of at least two-thirds of the voting power of the issued and outstanding shares of our capital stock entitled to vote thereon shall be required to amend or repeal provisions of our bylaws relating to meetings of stockholders, including the provision that stockholders may not take action by written consent in lieu of a meeting, the nomination and election of directors, vacancies on the board of directors, and our authority to provide indemnification for our directors and officers.

The foregoing provisions of our certificate of incorporation and bylaws could discourage potential acquisition proposals and could delay or prevent a change in control. These provisions are intended to enhance the likelihood of continuity and stability in the composition of our board of directors and in the policies formulated by our board of directors and to discourage certain types of transactions that may involve an actual or threatened change of control. These provisions are designed to reduce our vulnerability to an unsolicited acquisition proposal. The provisions also are intended to discourage certain tactics that may be used in proxy fights. However, such provisions could have the effect of discouraging others from making tender offers for our shares, and, as a consequence, they also may inhibit fluctuations in the market price of the common stock that could result from actual or rumored takeover attempts. Such provisions also may have the effect of preventing changes in our management or delaying or preventing a transaction that might benefit you or other minority stockholders.

Limitations on Liability and Indemnification of Officers and Directors

Our certificate of incorporation and bylaws provide indemnification for our directors and officers to the fullest extent permitted by the DGCL. We have entered into indemnification agreements with each of our directors that are, in some cases, broader than the specific indemnification provisions contained under Delaware law. In addition, as permitted by Delaware law, our certificate of incorporation includes provisions that eliminate the personal liability of our directors for monetary damages resulting from breaches of certain fiduciary duties as a director. The effect of this provision is to restrict our rights and the rights of our stockholders in derivative suits to recover monetary damages against a director for breach of fiduciary duties as a director, except that a director will be personally liable for:

These provisions may not be held to be enforceable for violations of the federal securities laws of the United States.