5500 Series Rev D Pilot Operated Pressure Relief Vent With Pipe Away; PN16 Flange Connection; 4" Inlet Size; 4" Outlet Size; 316 Stainless Steel Body, 316 Stainless Steel Bolt-In Seat Ring; Fluorocarbon Elastomer (FKM) Actuator Diaphragm, Pilot Seat, And Pallet Diaphragm; With Special 34.7-86.8 mbar Range Spring, Vendor To Supply Pressure Reducing Air Set For Air Assist; Opt-A: Internal Sensing, Pilot Exhaust To Atmosphere With Manual Blowdown Valve