MODEL "D"SALES B KIT FOR PRODUCT CODE: 2D4-3B57-144000M0C; PRESSURE REDUCING REGULATOR,TFE GASKETS (OPT-45) 1/2" SIZE; BRONZE BODY & SPRING CHAMBER; B5 TRIM: BRASS WITH TFE SEAT,PHOS.BRONZE DIAPHRAGM; OPT-4: STABILIZER (RECOMMENDED FOR GASEOUS SERVICE ONLY); OPT-55: CLEANED FOR OXYGEN SERVICE PER SPEC #S-1134;