Model D Rev D Pressure Reducing Regulator For General Service; 1/2" Line Size; Carbon Steel Body And Spring Chamber; S40V Trim: 316 Stainless Steel With Fluorocarbon Elastomer (FKM) Seat And Diaphragm; NPT Threaded End Connections; 30-80 PSI Range Spring; Opt-4: Piston Stabilizer For Gaseous Service; Opt-25S: Stainless Steel Vented Spring Chamber Plug