Unicel C-8420 Replacement Filter Cartridge for 200 Square Foot Hayward C1900RE, Waterway Pro Clean 200 Diameter: 8 15/16-inch; length: 28 3/16-inch Top end cap: open with molded gasket, 4 0/0-inch inner diameter; bottom end cap: open with molded gasket, 4 0/0-inch inner diameter Pleat count: 236; filter media: 4-ounce reemay 2040; filter area: 200 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications