Model D Rev D Pressure Reducing Regulator For General Service; 1/2" Line Size; Ductile Iron Body And Spring Chamber; Special B2 Trim Per SPQ 53375: Brass With BUNA-N (NBR) Seat And 302 Stainless Steel Diaphragm; NPT Threaded End Connections; 10-40 PSI Range Spring; Polyethylene Vented Spring Chamber Plug