1/2'' Multi-Purpose, Self-Priming, Pure Copper Check Valve by Original Safety Siphon - 3.5 Gallons Per Minute Flow Rate - Great for Homebrewing and Wine Making

Works great! Installed it on 1/2” PVC tubing. When I first tried it, I have to admit I couldn’t get it to work. Once I got the proper technique, quick short 1-2” back and forth strokes, it worked like a charm.

I use these to get the rain water off my pool cover . Works great and it’s super easy