Unicel C-5623 Replacement Filter Cartridge for 23 Square Foot Pac-fab Diameter: 5 5/16-inch; length: 13 9/16-inch Top end cap: open, 2 0/0-inch inner diameter; bottom end cap: open, 2 0/0-inch inner diameter Pleat count: 84; filter media: 4-ounce reemay 2040; filter area: 23 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications