The Mack vacuum valves offered are suitable for coarse through extreme ultra high vacuum operating pressure ranges. Both manual and pneumatic valves are offered as standard. Vacuum and Ultra High Vacuum valves Isolate vacuum volumes from pumps and control gas flow. Mack valves are designed for 3 million cycles with warranty of 1.5 million cycles (or 12 months). Valve body is made of 304 stainless steel. Welded bellows are made of AM350 for long life. To guarantee long lasting seal life, actuator housings are machined and honed to micron precision unlike most tube-housing constructed valves which are neither round nor straight. Mack's standard pneumatic valves up to 50mm air-open / air-close. Valve size goes up to 630mm. Optional "pneumatic lock" is available.