Unicel 4CH-949 Replacement Filter Cartridge for 50 Square Foot Rising Dragon, Waterway, Dynasty Spas Diameter: 4 15/16-inch; length: 13 1/2-inch Top end cap: v-groove semi-circular handle, 0-inch inner diameter; bottom end cap: 2-inch female sae thread, 0-inch inner diameter Pleat count: 210; filter media: 3-ounce reemay 2033; filter area: 50 square feet Get more efficient filtration and better water clarity with Unicel filters Longer time between cleanings; meets oem specifications