Product Description The Spa Frog Cartridge Kit from King Technology includes 1 blue Spa Frog Mineral Cartridge and 3 yellow Spa Frog Bromine Cartridges. Each Mineral Cartridge lasts up to 4 months, and each Bromine Cartridge lasts 2-4 weeks, depending on use. The cartridges can be used either with a pre-existing floating holder (sold separately as Spa Frog Floating System), in a manufacturer installed in-line system or as stand alone floaters in your spa or hot tub. The Mineral Cartridge and Bromine Cartridge can reduce chlorine use up to 50%. Used cartridges can be recycled.