Model "123" Back Press Relief Regulator,Tfe Gaskets; 1" Size; Cf8m Body & Spring Chamber (Opt-36), Cryogenic Construction;Opt-55: Cleaned For Oxygen Service Per Spec #S-1134; S1 Trim: 316SST Cylinder & Plug With Metal Seat,302SST Diaphragm; Opt-39: Socket Weld Ends; 35-100 PSIG SST Range Spring