Model 31-N Rev A Low Pressure Reducing Gas Regulator; 3/4" Body Size, #6 (0.375") Orifice; Sales Kit A; Stainless Steel Body And Lower Case, Carbon Steel Spring Chamber, Arrangement/Position 1, Internal Sensing Unless External Sensing Option Is Specified; S40N Trim: 316L Stainless Steel Internals, BUNA-N Seat And Diaphragm, Glass Filled Nylon Load Ring