Unicel C-7633 Replacement Filter Cartridge for 33 Square Foot Purex CF-33/100 Diameter: 7-inch; length: 14-inch Top end cap: open, 2 15/16-inch inner diameter; bottom end cap: open, 2 15/16-inch inner diameter Pleat count: 99; filter media: 6-ounce reemay 2470; filter area: 33 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications