This check valve is designed to use with Hayward Perflex extended-cycle basic and D.E. filter models EC65A, EC75A, EC65, EC75, EC50A, EC30, EC40, EC40AC, EC50AC, I_PFPPTS, EC50C80X5S, EC40C90 Series and also compatible with ASL filter, ReGenX grid element D.E. filter and Star-Clear cartridge filter models C85075XES, C125080X5S, RG450, RG700. Weight 9.3-pound.