This 1/2″ Sch 80 PVC True Union Ball Check Valve, EPDM, (FNPT x FNPT) prevents flow from going in one direction using a ball inside the valve that seals with back pressure. a male adaptor, threaded pipe or pipe nipple connects to this part. Sch 80 PVC is robust and durable, perfect for commercial and industrial applications. EPDM seals provide effective sealing with resistances to several chemicals over a wide range of temperatures. Our close relationship with our suppliers means we can give you the best price.