Safety Check Valve is an essential accessory for circulating pump. Its main function is to aviod damaging the impeller when pump stops working. LASWIM Safety Check Valve is specially designed for swimming pool and spa and it relies on the flow of the liquid itself to turn on and turn off the seal baffle automatically,then form the direction flow of the liqiud.It ensures the direction flow of water from swimming pool and spa and prevents water from backflow.