Exhibit 99.1 EMPLOYMENT AGREEMENT EMPLOYMENT AGREEMENT dated as of April 25, 2005 ("Employment Agreement"), by and between MKS Instruments, Inc., a Massachusetts Corporation (the "Corporation"), and Gerald G. Colella, of Seabrook, NH (the "Employee")....Employment Agreement • April 27th, 2005 • MKS Instruments Inc • Industrial instruments for measurement, display, and control • Massachusetts
