Model "DA1" Pressure Reducing Regulator (Series I); Body Size 2",Standard Diaphragm Construction; Carbon Steel Body & Carbon Steel Spring Chamber; 17-4ph SST Trim, 316l SST Cage, Nbr Seat, Nbr Diaphragm,;Nbr Static Seal, SST/Tfe U-Cup Dynamic Seal; 300 Lb Raised Face Flanges; 15-50 PSIG Range Spring; External Sensing, Standard - Flow To Open Direction; Opt-25: 1/4"Npt Female Spring Chamber Vent Tap