4 PACK Hayward CX580XRE, Swim Clear C3025, Replacement Filter Cartridges, Unicel C-7483, Pleatco PA81, Filbur FC-1225 Swimming Pool Filter Cartridges LENGTH 19 5/8 inches ... OUTER DIAMETER 7 inches ... INNER DIAMETER 3 inches 325 square feet 176 PLEATS PLEASE DOUBLE CHECK YOUR CARTRIDGE MEASUREMENTS MADE IN THE USA Replacement Cartridge fits: Hayward CX580XRE, Swim Clear C3025, Pleatco PA81, Filbur FC-1225, Aladdin 18101, Unicel C-7483