Model 345 Rev B Pressure Reducing Regulator, OPT-45: Oxygen Compatible Gasket; 3/4" Line Size; Stainless Steel Body With Bronze Spring Chamber; S3 Trim: 316 Stainless Steel With PTFE Seat, Fluorocarbon Elastomer O-Rings, Fluorocarbon Elastomer Gasket; NPT End Connections; 200-600 PSIG Range Spring; OPT-55: Cleaned For Oxygen Service Per Cashco Specification S-1134