Model "1000HP-1+8" Diff Press Reg,Dbl Diaph,Graphite/Nbr Gaskets; 1" Size,Gaseous Jet; Wcc Body,Wcb Spring Chamber With Closing Cap; B5 Trim: Brass With Tfe Seat,Phos.Bronze Diaphragm; Npt Screwed; 10-40 PSId Range Spring; Opt-17: Piston Spring; Opt-Bp: Solid Plug For Spring Chamber; Opt-65: Double 3/4" Npt Tapped Spring Chamber