Duckbill Check Valve 1:material:rubber,flange 2:sizes:DN25mm~DN5000mm 3: ... -term partner:FLSmidth Co.,A/S 4:12 years duckbill check valve,rubber duckbill valve,flange duckbill valve Flange duckbill valve ... bubble air diffusers Sparging nozzles Application figure: Certificates obtained: duckbill check valve,rubber duckbill valve,flange duckbill valve