Catit Triple Action Fountain Filters provide three-in-one filtration so your cat can enjoy clean and odor-free drinking water, directly from their Catit Flower Fountain.Suitable for the original (green) Flower Fountain, as well as our stainless steel and LED model, these Catit Flower Fountain Filter cartridges come in packs of 2, 5 and 12.Catit Triple Action Fountain Filters include three filtering components to clear your cat’s drinking water:•The filter’s outer layer, made of cotton mesh, catches stray hairs and other debris.•Active carbon helps remove foul odors and impurities.•The ion exchange resin filters out excess calcium and magnesium from tap water, softening it. In large amounts, these minerals can build up in your cat’s lower urinary tract, which can in turn lead to urinary tract disease.For best results, change filters every 30 days.