Fenwick & West Represents Ion Systems in Acquisition by MKS Instruments

November 28, 2005

Fenwick & West LLP represented Ion Systems, Inc. in its recently announced acquisition by MKS Instruments, Inc. (NASDAQ: MKSI). Ion Systems is a leading air ionization technology company with products for advanced manufacturing processes. MKS Instruments will pay approximately $70 million in cash for Ion Systems. The transaction is subject to closing conditions, and is expected to close in six to eight weeks and to be accretive in future quarters.

More information about the transaction can be obtained from the MKS Instruments Web site.

The Fenwick & West transaction team consisted of corporate attorneys: David Healy, Tahir Joel Naim; IP attorney Al Smith; and litigation attorney Darryl Woo.

About Fenwick & West

Fenwick & West provides comprehensive legal services to high technology and life sciences clients of national and international prominence. The firm was ranked by MergerMarket as the #1 U.S. Legal Advisor for Technology Industry M&A in 2004.