Hot Tub Replacement Cartridge for use with Frog Ease Floating System - Hot Tub Maintance System Supports Less Chlorine Use - 3 PackBrand: Izayoi Features: Hot Tub Replacement Cartridges: The Cartridges are designed for use with the Frog Ease Floating System; perfect for hot tubs up to 600 gallons Self Regulating Water TreatmentThe Cartridges require no maintenance or monitoring; each cartridge lasts 3 to 4 weeks depending on the size of your tub and how often it is used Seamless Compatibility Works exclusively with the Frog Mineral Cartridge for quick and hassle free installation