Model "2171" Back Pressure Relief Regulator, Tfe Gasket/O-Ring; 1/4" Size, Angle Design (Two Side Inlets - Bottom Outlet); 316l SST Body, Bronze Spring Chamber; S3 Trim: 316l SST With Tfe Seat,Neoprene (Bc) Diaphragm; Npt Screwed; 5-30 PSIG Range Spring; Opt-86: Inlet Pressure Gauge (Includes Opt-85: Inlet Body Gauge Tap)