Model 123 Rev C Back Pressure Regulator, Graphite/NBR Gaskets; 1-1/2" Line Size; Sales Kit A; Stainless Steel Body With Carbon Steel Spring Chamber; S40T Trim: 316 Stainless Steel With PTFE Seat, Fluorocarbon Elastomer (FKM) Diaphragm; Per SPQ Number 56042: With Option-9 (TFE Diaphragm Cover)