The MAC 54 Series is a 3-way balanced spool valve piloted by a small direct operated balanced poppet valve. This is an extremely virsatile valve: 1. It can be converted for use in vacuum. 2. It can be changed from a Normally Closed function to a Normally Open function. Huge flow in a compact package size is the best way to describe this valve series. 3. It also can be converted to a remote air operated valve by removing the solenoid pilot assembly - just to name a few. For information regarding certifications (such as UL, CSA, RoHS and CE) please visit the Get Support pages on our website.