Unicel C-7492 Replacement Filter Cartridge for 100 Square Foot Pac-fab Seahorse-400 Diameter: 7-inch; length: 24 3/4-inch Top end cap: open, 2 5/8-inch inner diameter; bottom end cap: open, 2 5/8-inch inner diameter Pleat count: 150; filter media: 4-ounce reemay 2040; filter area: 100 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications