Investor Presentaiton

Important Additional Information Will be Filed with the SEC ESI plans to file with the SEC and mail to its stockholders a Proxy Statement in connection with the transaction. Additionally, MKS and ESI will file other relevant documents with the SEC in connection with the transaction. The Proxy Statement and other documents to be filed with the SEC by MKS and ESI will contain important information about MKS, ESI, the transaction and related matters. Investors and security holders are urged to read the Proxy Statement and other documents to be filed with the SEC by MKS and ESI carefully when they are available. Investors and security holders will be able to obtain free copies of the Proxy Statement and other documents filed with the SEC by MKS and ESI through the web site maintained by the SEC at www.sec.gov. In addition, investors and security holders will be able to obtain free copies of the Proxy Statement from ESI by visiting the Investor Relations section of ESI website (www.esi.com) or by directing a request to ESI, Attn: Investor Relations, at 13900 N.W. Science Park Drive, Portland, Oregon 97229. MKS and ESI, and their respective directors and executive officers, may be deemed to be participants in the solicitation of proxies in respect of the proposed transaction. Information regarding MKS' directors and executive officers is contained in MKS' Form 10-K for the fiscal year ended December 31, 2017 and its proxy statement dated March 28, 2018, which are filed with the SEC. Information regarding ESI's directors and executive officers is contained in ESI's Form 10-K for the fiscal year ended March 31, 2018 and its proxy statement dated July 10, 2018, which are filed with the SEC. To the extent holdings of securities by such directors or executive officers have changed since the amounts disclosed in each company's respective proxy statement, such changes have been or will be reflected on Statements of Change in Ownership on Form 4 filed with the SEC. Additional information regarding the participants in the solicitation of proxies in respect of the proposed transaction and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the Proxy Statement and other documents to be filed with the SEC by MKS and ESI when they are available. ••mks MKS PROPRIETARY 3

View entire presentation