Product Description: The Pet Water Fountain Filter Cotton provides clean, fresh water to your pet. The external polyester layer on each filter captures hair and debris and the charcoal removes odors and eliminates bad taste. Notice: 1. This product is a replacement filter for pet water dispensers, and does not include water dispensers. 2. The activated carbon filter should be replaced every 2 weeks. 3. Tips: Please soak in water for five minutes before use. 4. Since filters come in many shapes, check your cat fountain and check if the filters match.