The V812 Series Vacuum Generators provides an economical vacuum source for all your Hold Fast vacuum chucking systems. Only requires a basic 2CFM compressor. The V812 operates optimally with 80-90 PSI Air pressure. Easy vacuum adjustment knob ideal for lower start up vacuum required with Stabilizing Resin chambers. 25+ In Hg vacuum at sea level. small, compact, and quiet - just the light sound of air escaping from the case. Tip: Mount closely to the working area with double-sided tape, Velcro, or magnets to provide easy reach for control of vacuum.