MODEL "DA4" PRESSURE LOADED REDUCING REGULATOR (SERIES IV)-PLPRV BODY SIZE 1/2",STANDARD DIAPHRAGM CONSTRUCTION; SALES KIT A; CARBON STEEL BODY & CARBON STEEL LOADING CHAMBER; SPECIAL TRIM MATERIALS; PER SPQ NUMBER 55985 SPECIAL 17-4PH SST TRIM, 316L SST CAGE, C-TFE SEAT, FKM DIAPHRAGM FKM STATIC SEAL, O-RING DYNAMIC SEAL