MODEL "BQ" BACK PRESS RELIEF REGULATOR, TFE GASKETS 1/2" INLETS,1/2" OUTLET; SALES KIT B; BRONZE BODY & SPRING CHAMBER (OPT-5), CRYOGENIC CONSTRUCTION OPT-55: CLEANED FOR OXYGEN SERVICE PER SPEC #S-1134; B5 TRIM: BRASS WITH TFE SEAT,PHOS.BRONZE DIAPHRAGM; SPECIAL RANGE SPRING; PER SPQ NUMBER 52634 250-350 SST RANGE SPRING;