Product DescriptionFeatures:Most filters on the market are made from activated carbon. But our pet fountain filters are made from high quality activated carbon, ion exchange resin and cotton mesh. The water is deeply purified and safer. High Quality Assurance Our filters consist of premium activated carbon, ion exchange resin and cotton mesh, which are high quality assurance. Resin exchange - softens tap water. Activated carbon eliminates odors, keeps water tasting fresh. Cotton mesh - neatly captures hair, sediment and debris. Notes: Please rinse the filter thoroughly with water before use. Replace every 2-4 weeks to maintain water freshness. Replace more frequently with multiple animals using the fountain. A small amount of carbon dust may be released during the life of the filter, which is not not harmful to your pet.