The Catit PIXI Fountain Filter will clean your cat’s drinking water in 3 ways. It filters out debris, removes odours and impurities, and even softens the water by reducing magnesium and calcium levels. When present in high quantities, these minerals can accumulate in your cat’s lower urinary tract and lead to urinary tract diseases. Filters out debris Removes odours and impurities Softens tap water Fits all Catit PIXI drinking fountains