EXHIBIT 1 --------- AGREEMENT AS TO JOINT FILING OF SCHEDULE 13G -------------------------------------------- Each of the undersigned hereby affirms that it is individually eligible to use Schedule 13G, and agrees that this Schedule 13G is filed on its behalf. Date: May 19, 2006 SILLC HOLDINGS, LLC By: /s/ Peter F. Reilly --------------------------------- Name: Peter F. Reilly Title: Vice President, Chief Financial Officer, Treasurer and Secretary STRATEGIC INDUSTRIES, LLC By: /s/ Peter F. Reilly --------------------------------- Name: Peter F. Reilly Title: Vice President, Chief Financial Officer, Treasurer and Secretary CITIGROUP VENTURE CAPITAL EQUITY PARTNERS, L.P. By: CVC Partners, LLC Title: General Partner, Citigroup Venture Capital Equity Partners, L.P. By: /s/ Thomas F. McWilliams --------------------------------- Name: Thomas F. McWilliams Title: Managing Partner CVC PARTNERS, LLC By: /s/ Thomas F. McWilliams --------------------------------- Name: Thomas F. McWilliams Title: Managing Partner CITIGROUP VENTURE CAPITAL GP HOLDINGS LTD. By: /s/ Anthony P. Mirra --------------------------------- Name: Anthony P. Mirra Title: Vice President COURT SQUARE CAPITAL LIMITED By: /s/ Anthony P. Mirra --------------------------------- Name: Anthony P. Mirra Title: Vice President CITICORP BANKING CORPORATION By: /s/ William H. Wolf --------------------------------- Name: William H. Wolf Title: Senior Vice President CITIGROUP INC. By: /s/ Ali L. Karshan --------------------------------- Name: Ali L. Karshan Title: Assistant Secretary