Model 1164 Rev B Back Pressure Relief Regulator, Aramid/SBR Gaskets; 1-1/2" Line Size; Ductile Iron Body With Cast Iron Spring Chamber; S9 Trim: 316 Stainless Steel With PTFE Seat, PTFE Coated 302 Stainless Steel Diaphragm; NPT End Connections; 30-80 PSIG Range Spring