Model "123" SALES A KIT FOR PRODUCT CODE: 8C4-3B57-1C000000A; Cryogenic Back Press Relief Regulator,Non-Asb Gaskets; 1/2" Size; Bronze Body & Spring Chamber (Opt-5),Special Cleaning #S-1134(Opt-55); B5 Trim: Brass With Tfe Seat,Phos.Bronze Diaphragm;