For 263042Z 2-Inch 2-Way Check Valve, Compatible with CPVC 263042, 1.5″ and 2″ D
There is an arrow on the cover, it shows the direction of the water flow. NOT compatible with FullFloXF 2-Way & 90 Degree check valves 263060 & 263077. Effectively prevent water leakage caused by backflow in your pool when your pool pump is inactive.