... rubber,steel 4,12 years OEM manafacturer experience rubber check valves,duckbill valve,rubber duckbill valve 1: Product Introduction 1:Rubber ... 3:During the forward operation,water flows in from the inlet,and the lower water pressure will open the valve,the ... an ideal product to replace flat valves. 2:Rubber Check Valve CharateristicsCompared with traditional flat valves,it owns obvious advantages: 1, ...