Model D Rev D Pressure Reducing Regulator For General Service; 1/2" Line Size; Sales Kit B; Stainless Steel Body And Spring Chamber; SK Trim: 316 Stainless Steel With Fluorocarbon Elastomer (FKM) Seat And Diaphragm; Opt-4: Piston Stabilizer For Gaseous Service; Opt-55: Oxygen Cleaning Per Cashco Specification S-1134