The PetSafe Drinkwell Replacement Carbon Water Filters 4 Pack #6 PAC00-13906 are designed for use with PetSafe water fountains. Made from activated carbon derived from coconut shells, these filters effectively remove impurities and contaminants from your pet's drinking water. With a life stage suitable for all stages and a pack of 4 filters included, this product ensures a clean and safe water supply for your furry friends. The filters are easy to install and provide a convenient solution for maintaining your pet's hydration needs.