Unicel C-7497 Replacement Filter Cartridge for 100 Square Foot Waterco, Jandy CT-100 Diameter: 7 1/4-inch; length: 29 1/2-inch Top end cap: open with step, 3-1/16-inch inner diameter; bottom end cap: open with step, 3-1/16-inch inner diameter Pleat count: 134; 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