Model "4381" Pressure Reducing Regulator, Tfe Gasket/O-Ring; 1/2" Size; 316l SST Body & Cf3m SST Spring Chamber; S40t Trim: 316l SST With Tfe Seat,Fluorocarbon Elastomer (Fkm);Diaphragm; With Special Socket Weld End Connections; 5-30 PSIG Range Spring; Opt-4: Stabilizer (Recommended For Gaseous Service Only); Opt-40SST: Construction Per Nace Standard Mr0175