PVC Spring Flapper Check Valve 1/2-Inch Clear with Thread End Connectors Our PVC Swing Check Valve is excellent for preventing backflow into your water system during routine cleanings, backwashing, etc. Made in the USA from high quality PVC. You will notice this check valve is constructed from strong, durable material and has a sleek design. 1/2 lb. Spring-Loaded Gate Mechanism keeps the flapper in the "Closed" position and allows installation in any orientation. Much less inline restriction than a conventional check valve. We recommend Check Valves be installed on pools, pumps, filters, ponds, aquariums, sprinkler systems, irrigation systems, and other projects.