Valve Isolation 40mm Non Return EmauxEngineered by Emaux, the 40mm Isolation Valve with Non Return (check) functionality delivers precise flow control and reliable backflow protection for 40mm PVC pressure piping. Built for pools, irrigation, and household water lines, it keeps your system efficient and safe without unnecessary downtime. One way flow with built in non return valve prevents backflow and siphoning, safeguarding downstream equipment and maintaining clean, pressurized lines.