Unicel 7CH-40 Replacement Filter Cartridge for 40 Square Foot Top Load, Coleman Spas, Vita Spas Diameter: 7-inch; length: 9 3/4-inch Top end cap: semi-circular handle, 0-inch inner diameter; bottom end cap: 1-1/2-inch male thread/mpt, 0-inch inner diameter Pleat count: 178; filter media: 3-ounce reemay 2033; filter area: 40 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications