Thermoplastic [PVC, Polypropylene, or PVDF (Kynar)] Air-Piloted pressure regulator, [ 1/4" through 2" (3" in PVC only)] NPT threads. Valve to have a one piece body housing containing the inlet port, outlet port, valve seat, and pressure sensing orifice. Regulator is to have a piston with a fabric reinforced [EPDM, or Viton] rolling diaphragm sensing the downstream pressure and providing for maximum sensitivity and control accuracy. The shaft connecting the piston and the valve seat seal assembly shall have a double u-cup seal for safety. Two, large-surface, rolling diaphragm seals isolate the air chamber from downstream pressure sensing liquid. All units are to be 100% individually tested at the factory. As manufactured by Plast-O-Matic Valves, Inc., Cedar Grove, NJ USA.