Model D Rev D Pressure Reducing Regulator For General Service; 1/2" Line Size; Bronze Body With Ductile Iron Spring Chamber; S1 Trim: 316 Stainless Steel Metal Seat And 302 Stainless Steel Diaphragm; NPT Threaded End Connections; 2-15 PSI Range Spring; Opt-25S: Stainless Steel Vented Spring Chamber Plug