Unicel 35sqft Rainbow 9.25in Cartridge Diameter=4-15/16in.; Length=9-1/4in.; Top=2-1/8in.; Bottom=2-1/8in. Used On: Aber Hot Tubs (Canada) 03FIL1300, Belize Spas, Bullfrog Spas, Clearwater Spas, Coast Mountain Spas (Canada), Columbia Spas, Crystal Water Spas (Canada), Custom Molded Products, Great Lakes Home and Resort, Hydro Pool Industries, Infinity Spas TN, Moose Mountain Spas (Canada), Orca Bay Spas, Rec Warehouse 303557, Sun Coast Spas, Waterway Plastics 817-3501. Cross Reference 201974300, 25393, C4335, PRB35-IN-3, PRB35IN3, 17-2482