For use with Spa Frog floating and In-Line Systems. When the Mineral Cartridge is used on setting 6 the cartridge will last 4 months. The item “5 Spa Frog Mineral Cartridges” is in sale since Saturday, June 13, 2015. This item is in the category “Home & Garden\Yard, Garden & Outdoor Living\Pools & Spas\Spas & Hot Tubs”. The seller is “mman3229″ and is located in Yonkers, New York. This item can be shipped to United States.