Unicel 6CH-49 Replacement Filter Cartridge for 50 Square Foot Sunrise Spas Diameter: 6-inch; length: 8 1/4-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: 213; filter media: 3-ounce reemay 2033; filter area: 36 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications