Model "2171" Back Pressure Relief Regulator, Tfe Gasket/O-Ring; 3/8" Size, Sales Kit B; Angle Design (Two Side Inlets - Bottom Outlet); 316l SST Body, Bronze Spring Chamber; S1 Trim: 316l SST Metal Seat,302SST Diaphragm; 360-500 PSIG Range Spring (Includes Opt-80: High Inlet Pressure;Construction)