Unicel C-8610 Replacement Filter Cartridge for 100 Square Foot Hayward CX1100RE Diameter: 8 1/2-inch; length: 23 5/16-inch Top end cap: open with molded gasket, 4 0/0-inch inner diameter; bottom end cap: open with molded gasket, 4 0/0-inch inner diameter Pleat count: 153; 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