Model 1049 Rev A Pilot Operated Vent Valve; Carbon Steel Body; 2" Inlet X 3" Outlet Mates With ASME 150 Flanged End Connections; Buna-N Soft Seats; Standard Configuration With Internal Sensing And Pilot Exhaust To Atmosphere; BUNA-N Actuator Diaphragm; 1.2 - 4.0" wc Low Pressure Range With Special External Air Assist Pilot