Model BGR-1 Pilot Operated Back Pressure Relief Regulator; Body Size 1",; Carbon Steel Body & Carbon Steel Loading Chamber; 316l SST Trim, Bc Seat And Diaphragm;V-Tfe Static Seal, Bc O-Ring Dynamic Seal,;Pilot W / Nbr Seat & Ptfe Diaphragm,; 150 Lb Raised Face Flanges; 4.0-12.0" Wc Range Spring; SST Tubing, Self Contained Sensing For Positive Pressure Schematic; Opt-40: Construction Per Nace Standard Mr0175