MODEL "123-1+6+S" DIFF BACK PRESS RELIEF REGULATOR,NON-NACE SERVICE 1-1/2" SIZE,3/4" REDUCED ORIFICE; WCB BODY & SPRING CHAMBER; S40S TRIM: 316SST METAL SEAT,FLUOROCARBON ELASTOMER (FKM) DIAPHRAGM; OPT-30: 600 LB RAISED FACE FLANGES; 20-55 PSID RANGE SPRING; PER SPQ/MA DRAWING NUMBER 32935 ;