5500 Series Rev D Pilot Operated Pressure Relief Vent With Pipe Away; Mates With ASME 150 Flange Connection; 2" Inlet Size; 2" Outlet Size; Carbon Steel Body, 316 Stainless Steel Bolt-In Seat Ring; EPDM Actuator Diaphragm, Pilot Seat, And Pallet Diaphragms; 2.1" - 12.0" wc Pressure Spring Range; Standard: Internal Sensing With Pilot Exhaust To Main Valve Outlet And Backflow Preventer