Under the Securities Exchange Act of 1934
(Amendment No.  1)*

(Name of Issuer)

(Title of Class of Securities)

(CUSIP Number)

(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications)

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D and is filing this Schedule because of Rule 13d-1(e), Rule 13d-1(f) or 13d-1(g), check the following box: o

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act.

(1)  Includes 469,395 shares owned by the Walter C. Zable Trust U/A/D dated 2/7/06 and 232,746 shares held in trusts for Mr. Zable’s children.  Mr. Zable has sole voting and dispositive power over such shares as the trustee of such trusts, and disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein.

(2) Includes (a) 3,244,527 shares (12.1%) owned by the Zable QTIP Marital Trust Dated 9/18/78, (b) 2,290,877 shares (8.6%) owned by The Survivor’s Trust Created Under the Zable Trust Dated 9/18/1978, (c) 34,884 shares owned by the Zable Reverse QTIP Marital Trust dated 9/18/78, and (d) 16,108 shares owned by the Zable Non-QTIP Marital Trust dated 9/18/78.  Mr. Zable and Karen F. Cox share voting and dispositive power over such shares as co-trustees of such trusts, and each disclaims beneficial ownership of such shares except to the extent of his or her pecuniary interest therein.

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(3) Includes (a) 3,244,527 shares (12.1%) owned by the Zable QTIP Marital Trust Dated 9/18/78, (b) 2,290,877 shares (8.6%) owned by The Survivor’s Trust Created Under the Zable Trust Dated 9/18/1978, (c) 34,884 shares owned by the Zable Reverse QTIP Marital Trust dated 9/18/78, and (d) 16,108 shares owned by the Zable Non-QTIP Marital Trust dated 9/18/78.  Walter C. Zable and Ms. Cox share voting and dispositive power over such shares as co-trustees of such trusts, and each disclaims beneficial ownership of such shares except to the extent of his or her pecuniary interest therein.  Also includes 240,000 shares held in trusts for Ms. Cox’s children.  Ms. Cox and her spouse share voting and dispositive power over such shares as co-trustees of such trusts and each disclaims beneficial ownership of such shares except to the extent of his or her pecuniary interest therein.

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Explanatory Note:

This Amendment No. 1 (this “Amendment”) amends and supplements the statement on Schedule 13D initially filed on behalf of the Reporting Persons with the Securities and Exchange Commission (“SEC”) on July 17, 2012 (collectively, the “Statement”).  The Reporting Persons are filing this Amendment to report changes in their beneficial ownership since the previous filing of the Statement.  Except as set forth below, all previous Items set forth in the Statement are unchanged.  Capitalized terms used but not defined herein shall have the meanings given to such terms in the Statement.

Item 4.                           Purpose of Transaction.

Item 4 of the Statement is amended by adding the following paragraphs immediately prior to the last paragraph thereof:

On May 15, 2013, the Zable QTIP Marital Trust Dated 9/18/78, The Survivor’s Trust Created Under the Zable Trust Dated 9/18/1978 and the Zable Reverse QTIP Marital Trust Dated 9/18/78 (the “Selling Stockholders”) entered into an underwriting agreement (the “Underwriting Agreement”) with J.P. Morgan Securities LLC and Credit Suisse Securities (USA) LLC, as representatives of the underwriters named therein (the “Underwriters”), and the Company in connection with a secondary public offering of Shares as described in the prospectus filed by the Company with the SEC on May 16, 2013.  Pursuant to the Underwriting Agreement, on May 21, 2013, the Selling Stockholders sold 2,315,000 Shares to the Underwriters at a price of $43.69125 per Share, representing the public offering price of $45.75 per Share less underwriting discounts and commissions of $2.05875 per Share.  Of the 2,315,000 shares, the Zable QTIP Marital Trust Dated 9/18/78 sold 1,242,520 Shares, The Survivor’s Trust Created Under the Zable Trust Dated 9/18/1978 sold 1,057,207 Shares and the Zable Reverse QTIP Marital Trust Dated 9/18/78 sold 15,273 Shares.  The Shares were sold in order to raise funds to pay estate taxes.  Pursuant to the Underwriting Agreement, the Selling Stockholders also granted the Underwriters an option for 30 days to purchase up to 347,250 additional shares.  Of the 347,250 Shares, the Zable QTIP Marital Trust Dated 9/18/78 granted an option for 186,378 Shares, The Survivor’s Trust Created Under the Zable Trust Dated 9/18/1978 granted an option for 158,581 Shares and the Zable Reverse QTIP Marital Trust Dated 9/18/78 granted an option for 2,291 Shares.

Pursuant to lock-up agreements entered into in connection with the Underwriting Agreement, the Reporting Persons agreed not to sell, transfer or dispose of, directly or indirectly, any Shares or any securities exercisable or exchangeable for Shares without the prior written consent of J.P. Morgan Securities LLC for a period of 90 days after May 15, 2013, subject to extension under certain circumstances.  The form of such lock-up agreements is attached as an exhibit to the Underwriting Agreement.

The foregoing description of the Underwriting Agreement is qualified by reference to the full text of the Underwriting Agreement, a copy of which is filed as Exhibit 1.1 to Amendment No. 2 to the Company’s Registration Statement on Form S-1 filed with the SEC on May 8, 2013 and is incorporated herein by reference.

Item 5.                           Interest in Securities of the Issuer.

Item 5 of the Statement is amended and restated in its entirety as follow:

Item 6.                         Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

The description of the Underwriting Agreement in Item 4 hereof is incorporated herein by reference.

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Item 7.      Material to be Filed as Exhibits.

Item 7 of the Statement is amended by adding the following after the last paragraph thereof:

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SIGNATURES

After reasonable inquiry and to the best of each of the undersigned’s knowledge and belief, each of the undersigned hereby certifies that the information set forth in this statement is true, complete and correct.

Dated: May 30, 2013

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