The MAC 56 Series is a 3-way balanced spool valve piloted by a small direct operated balanced poppet valve. This is an extremely versatile 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 by simply rotating a function plate between the pilot and main valve bodies. 3. It can also 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.