... rubber,steel 4,12 years OEM manafacturer experience rubber check valves,duckbill valve,rubber duckbill valve 1: Product ... service life•Wide size,norminal size:DN50~DN1200mm3:Rubber Check Valve Application ScopeApplicable Scope:1:Sewage systems7: Stormwater outfall2 ... from sewage reservoirs12:Coarse bubble air diffusersSparging nozzles4:Rubber Check Valve Dimension This our basic sizes from DN50~1200mm ...