Jones Stephens has built its reputation over the years as a leader in the plumbing industry, providing the market with thousands of products to complete any project. ABS backwater valves prevent sewage backup in drainage systems by blocking backflow with a flapper that is forced into a closed position if sewage starts accumulating. Their stepped construction encourages water flow, and the flapper and cover have an elastomeric gasket to ensure a watertight seal. With a magnetic strip for underground detection and threaded access cover for easy inspection, maintenance is simple. Material: Acrylonitrile Butadiene Styrene (ABS).