U.S. Plastic Corp.® is your source for a wide variety of check valves. A check valve is a device used to stop the flow of media in one directions while allowing flow in the opposite direction. The closure member used is spherical or ball shaped. We carry many materials and sizes to meet most needs including PVDF, CPVC, polypropylene and PVC. We also carry numerous brands including Asahi®, Cepex, Hayward®, Nibco® and many others.