Spears S1720C20 PVC Clear Union Utility Swing Check Valve for Pools PVC clear dual swing union utility check valve is engineered for maximum flow, quick response and positive shutoff Offers a compact, high performance check valve for landscape and irrigation, pool and spa, aquaculture, OEM 1 and many general purpose applications Angled seat and weighted flapper for low-pressure seal Suitable for horizontal or vertical up-flow installations Socket, threaded or SR threaded end connections