Unicel C-5622 Replacement Filter Cartridge for 22 Square Foot Premier, Old Diameter: 5 3/16-inch; length: 11 7/8-inch Top end cap: open, 1-1/16-inch inner diameter; bottom end cap: open, 1 5/8-inch inner diameter Pleat count: 100; filter media: 6-ounce reemay 2470; filter area: 22 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications