... manafacturer experience Rubber Duckbill Valve,flange duckbill valve,rubber check valve 1: Product Introduction 1:Rubber check valve is made of rubber ... to the differential water pressure,safe,reliable,noiseless,no manual operation or maintenance 2, There is smaller resistence ... 5, Wide size,norminal size:DN50~DN1200mm3:Rubber Check Valve Application Scope Applicable Scope:1:Sewage systems7: Stormwater ...