These valves are for controlling downstream pressure to adjust set point. the valve closes when downstream pressure rises. Sizes:DN 15 TO 100 MOC:Body made of either CI ( A126 B), Cast Steel ( A216 GR WCB )Stainless Steel, CF8M Actuator with EPDM a351, cf8m actuator with epdm rolling diaphragm. All wetted parts are free of non-ferrous metal Springs:For three reduced pressure 5/60, 20/80,