Model "DA2" Differential Pressure Reducing Regulator (Series II)-PDRV; Body Size 1",Opt-81: Full Diaphragm Support Construction; Cf3m Body,316l SST Spring Chamber,1/8" Petcock Vent; 17-4ph SST Trim, 316l SST Cage, Pa Seat, Nbr Diaphragm,;Nbr Static Seal, SST/Tfe U-Cup Dynamic Seal; Special 600 Lb RTJ Flanges; 10-35 PSId Range Spring; Internal Sensing, Standard - Flow To Open Direction; Opt-65a: Double Tapped Spring Chamber,1/4" Npt