Model D Rev C Pressure Reducing Regulator With Graphite/NBR Gaskets; 1/2" Size; Cast Iron Body & Spring Chamber; B2 Trim: Brass With Buna-N (Nbr) Seat,Neoprene (Bc) Diaphragm; Npt Screwed; 70-150 PSIG Range Spring; Opt-4: Stabilizer (Recommended For Gaseous Service Only); Opt-25p: Screen For Spring Chamber Vent