Unicel C-7400 Replacement Filter Cartridge for 50 Square Foot Goldkey Diameter: 7-inch; length: 14 3/4-inch Top end cap: semi-circular handle, 0-inch inner diameter; bottom end cap: open, 1 7/8-inch inner diameter Pleat count: 143; filter media: 4-ounce reemay 2040; filter area: 50 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications