Model 1164 Rev B Back Pressure Relief Regulator, Aramid/SBR Gaskets; 1" Line Size; Ductile Iron Body With Cast Iron Spring Chamber; S36 Trim: 316 Stainless Steel With PTFE Seat, 302 Stainless Steel Diaphragm; NPT End Connections; 10-40 PSIG Range Spring; OPT-56: Cleaned For Non-Oxygen Service Per Cashco Specification S-1542