Model "DA1" Pressure Reducing Regulator (Series I); Body Size 3/4",Standard Diaphragm Construction; Carbon Steel Body & Carbon Steel Spring Chamber; Nace Trim, Pa Seat, Nbr Diaphragm;Nbr Static Seal, Elg/Tfe U-Cup Dynamic Seal; 300 Lb Raised Face Flanges; 100-300 PSIG Range Spring; Internal Sensing, Standard - Flow To Open Direction; Opt-25: 1/4"Npt Female Spring Chamber Vent Tap; Opt-40: Nace Construction Per Spec# Mr0175