Unicel C-7651 Replacement Filter Cartridge for 50 Square Foot Purex CF-50/150 Diameter: 7-inch; length: 19 5/8-inch Top end cap: open, 2 15/16-inch inner diameter; bottom end cap: open, 2 15/16-inch inner diameter Pleat count: 110; filter media: 6-ounce reemay 2470; filter area: 50 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications