Length: 19-1/8" Diameter: 8-3/8" Top opening: 2-3/16" OD slip Bottom opening: open hole 4-7/16" Replacement for Sundance Spas 800 Series Microclean Ultra Outer Cartridge   High-quality filtration fabric Break-resistant Guardian filter banding Durable coreless cartridge design Alternative filter names: 6473-165, AK-6473165, UFC-165, Sundance MicroClean Ultra   Used in spas made by Sundance   By Guardian Filtration Products • 819OUTR