Unicel C-7487 Replacement Filter Cartridge for 100 Square Foot Hayward CX870RE Diameter: 7-inch; length: 25 1/2-inch Top end cap: open with molded gasket, 3 0/0-inch inner diameter; bottom end cap: open with molded gasket, 3 0/0-inch inner diameter Pleat count: 164; filter media: 4-ounce reemay 2040; filter area: 100 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications