4 PACK Hayward CX870RE, Super Star Clear 4000 Replacement Filter Cartridges, Unicel C-7487, Pleatco PA100N, Filbur FC-1270 Swimming Pool Filter Cartridges LENGTH 25 1/2 inches ... OUTER DIAMETER 7 inches ... INNER DIAMETER 3 inches 4X100 square feet 164 PLEATS PLEASE DOUBLE CHECK YOUR CARTRIDGE MEASUREMENTS MADE IN THE USA Replacement Cartridge fits: Hayward CX870RE, Super Star Clear 4000, Unicel C-7487 Pleatco PA100N, Filbur FC-1270, Aladdin 19902