Model D Rev D Pressure Reducing Regulator For General Service; 3/8" Line Size; Ductile Iron Body And Spring Chamber; B2 Trim: Brass With BUNA-N (NBR) Seat And Neoprene (BC) Diaphragm; NPT Threaded End Connections; 30-80 PSI Range Spring; Opt-4: Piston Stabilizer For Gaseous Service; Polyethylene Vented Spring Chamber Plug