Keep your pet’s drinking water fresh, clean, and safe. Unlike most filters on the market made of only activated carbon, our filters are made of carbon, resin, and cotton mesh. The three step filtration will assure the quality of the water as well as enhance the taste of fresh water for your pets. Compatible with our automatic LED pet water fountain and others of the same size. To ensure the water is kept clean filters should be changed every 2 – 4 weeks.