Features: ??Design & Manufacture: GB ??Face to Face Dimension: GB  Flange end Dimension: ANSI 16.5 ,JB79,GB9113,DIN 2501 ??Inspect & Test: GB/T13927-92, GB/J9092 ??Operation: Manuel ??Pressure Rating: PN16, PN25, PN40, PN64 Standard Material Construction: ??Body/Bonnet: Cast Iron, Carbon Steel and Stainless Steel ??Disc: Cast Iron, Carbon Steel and Stainless Steel ??Secondary Disc/Seat: Stainless Steel ??Diaphragm: Stainless Steel ??Main Disc/Seat: Stainless Steel ??Piston: Stainless Steel ??Secondary Spring: Chrome Vanadium Steel ??Main Spring: Chrome Vanadium Steel ??Adjusted Spring: Silicon Manganese Steel ??Piston Ring: Alloy Cast Iron