... Check Valves and Duckbill Valves: Rubber check valve also known as: rubber sewage check valve, sewage rubber check valve, rubber check ... bottom of the duckbill valve, plus special apparatus, can reach 10 meters underwater.2) Service Life: the design life of two ... climate is bad, you can use five years, even as long as 10 years, but the proposed one-for five years to prevent ...