MODEL "D" PRESSURE REDUCING REGULATOR,TFE GASKETS (OPT-45) 1/2" SIZE; CF8M BODY & SPRING CHAMBER; S7 TRIM: 316SST WITH V-TFE SEAT, FLUOROCARBON ELASTOMER (FKM) DIAPHRAGM; OPT-4: STABILIZER (RECOMMENDED FOR GASEOUS SERVICE ONLY); OPT-55: CLEANED FOR OXYGEN SERVICE PER SPEC #S-1134