**Exhibit 3.18**

**RESTATED CERTIFICATE OF INCORPORATION**

**OF**

**AIRPAX HOLDINGS, INC.**

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***Adopted in accordance with the provisions***

***of §242 and §245 of the General Corporation Law***

***of the State of Delaware***

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The undersigned, on behalf of Airpax Holdings, Inc., a corporation duly organized and existing under and by virtue of the General Corporation Law of the State of Delaware (the “Corporation”), DOES HEREBY CERTIFY as follows:

**FIRST**: The Corporation filed its original Certificate of Incorporation with the Delaware Secretary of State on April 20, 2004under the name Blairpax, Inc. The Corporation filed a Restated Certificate of Incorporation with the Delaware Secretary of State on May 13, 2004 (the “Restated Certificate of Incorporation”). 

**SECOND**: The Board of Directors of the Corporation duly adopted resolutions in accordance with Section 242 and Section 245 of the GeneralCorporation Law of the State of Delaware authorizing the Corporation to amend, integrate and restate the Restated Certificate of Incorporation in its entirety to read as set forth in ***Exhibit A*** attached hereto and made a parthereof (the “Restated Certificate”). 

**THIRD**: In accordance with Section 228, Section 242 and Section 245 ofthe General Corporation Law of the State of Delaware, the Restated Certificate was duly approved and adopted pursuant by all of the holders of the issued and outstanding shares of capital stock of the Corporation entitled to vote thereon.

IN WITNESS WHEREOF, the undersigned on behalf of the Corporation for the purpose of amending and restating the Restated Certificate ofIncorporation of the Corporation pursuant to the General Corporation Law of the State of Delaware, under penalties of perjury does hereby declare and certify that this is the act and deed of the Corporation and the facts stated herein are true, andaccordingly has hereunto signed this Certificate of Restated Certificate of Incorporation this 14th day of August, 2007. 

 

**EXHIBIT A**

**RESTATED CERTIFICATE OF INCORPORATION**

**OF**

**AIRPAX HOLDINGS, INC.**

**ARTICLE ONE**

The name of the corporation is Airpax Holdings, Inc. 

**ARTICLE TWO**

The address of the corporation’s registered office in the State of Delaware is 160Greentree Drive, Suite 101, in the City of Dover, County of Kent, 19904. The name of its registered agent at such address is National Registered Agents, Inc. 

**ARTICLE THREE**

The nature of the business or purposes to be conducted or promoted is to engage inany lawful act or activity for which corporations may be organized under the General Corporation Law of the State of Delaware. 

**ARTICLEFOUR**

The total number of shares of capital stock that the Corporation has authority to issue is 1,000 shares of Common Stock, parvalue $0.01 per share. 

**ARTICLE FIVE**

The corporation is to have perpetual existence. 

**ARTICLE SIX**

In furtherance and not in limitation of the powers conferred by statute, the board of directors of the Corporation is expressly authorized to make, alteror repeal the by-laws of the Corporation. 

**ARTICLE SEVEN**

Meetings of stockholders may be held within or outside of the State of Delaware, as the by-laws of the Corporation may provide. The books of theCorporation may be kept outside the State of Delaware at such place or places as may be designated from time to time by the board of directors or in the by-laws of the Corporation. Election of directors need not be by written ballot unless theby-laws of the Corporation so provide. 

**ARTICLE EIGHT**

To the fullest extent permitted by the General Corporation Law of the State of Delaware as the same exists or may hereafter be amended, a director of this Corporation shall not be liable to the Corporation or itsstockholders for monetary damages for a breach of fiduciary duty as a director. Any repeal or modification of this ARTICLE NINE shall not adversely affect any right or protection of a director of the Corporation existing at the time of such repealor modification. 

**ARTICLE NINE**

The Corporation expressly elects not to be governed by §203 of the General Corporation Law of the State of Delaware. 

**ARTICLE TEN**

The Corporation reserves the right to amend, alter, change or repeal any provision contained in thiscertificate of incorporation in the manner now or hereafter prescribed herein and by the laws of the State of Delaware, and all rights conferred upon stockholders herein are granted subject to this reservation. 

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