Model "D" Pressure Reducing Regulator,Tfe Gaskets (Opt-45); 3/8" Size; Sales Kit B; Cf8m Body & Spring Chamber; S40t Trim: 316SST With Tfe Seat,Fluorocarbon Elastomer (Fkm) Diaphragm; Opt-4: Stabilizer (Recommended For Gaseous Service Only); Opt-55: Cleaned For Oxygen Service Per Spec #S-1134