Model "DA1" Pressure Reducing Regulator (Series I); Body Size 4",Standard Diaphragm Construction; Carbon Steel Body & Carbon Steel Spring Chamber; Hastelloy C Trim, Gf-Tfe Seat, Fkm Diaphragm;Fkm Static Seal, Hastelloy C U-Cup Dynamic Seal; 150 Lb Raised Face Flanges; 1-10 PSIG Range Spring; Internal Sensing, Standard - Flow To Open Direction; Opt-9: Tfe Diaphragm Cover,0.020"; Opt-25: 1/4"Npt Female Spring Chamber Vent Tap