Unicel C-9499 Replacement Filter Cartridge for 120 Square Foot Hayward CX1250RE, Muskin FE129 P/N 58040 Diameter: 9 1/4-inch; length: 19 5/8-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: 152; filter media: 4-ounce reemay 2040; filter area: 120 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications