The cat water fountain filter is compatible with PUPPY KITTY 2L ultra-quiet automatic water dispenser for cats and dogs. ☑ We recommend changing the filter every 2 to 4 weeks to keep it clean. fresh and clean water. 8 Pieces of high quality cat water fountain filter with cotton, resin and activated carbon.Filters hair and debris, removes odors and softens water, for a better taste of water. To prevent the carbon dust from rushing out, please rinse the filter with plenty of water before using it, and supply the clean water to cats and dogs.