Unicel C-7418 Replacement Filter Cartridge for 100 Square Foot Rec. Warehouse Diameter: 7 1/2-inch; length: 20 13/16-inch Top end cap: open, 2 15/16-inch inner diameter; bottom end cap: open, 2 15/16-inch inner diameter Pleat count: 177; 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