Model BQ Rev A Back Pressure Regulator, Graphite/NBR Gaskets; 1/2" Inlets,1/2" Outlet; Carbon Steel Body With Stainless Steel Spring Chamber; S40T Trim: 316 Stainless Steel With PTFE Seat, Fluorocarbon Elastomer (FKM) Diaphragm; NPT End Connections; 20-75 PSIG Range Spring; OPT-1: Closing Cap; Replacing Solar #120382