Features: Value pack of 4 filters. Compatible with YOUTHINK, HOMMI, ISYOUNG, KOALAD, HAPPYPAPA, PEDY, DADYPET, automatic flower fountain and other of the same size. Size: 5in(outer diameter), 1.5in(inner diameter).? The filter is made of resin and activated carbon to help remove chlorine, odor and organic pollutants from the water. To improve the water quality, three kinds of filtration (resin, charcoal, filter cotton fabric) can be used to remove impurities and debris from the outer polyester layer of each filter. The three steps of filtration can ensure the quality of your cat and improve the taste of your cat. It can last for 3-4 weeks to reach the standard water quality. We suggest that you change it in time to provide healthy water for your cat and dog and improve the water quality. 3-layer filtration system filtration deodorization purification: The first layer of PPF cotton microporous filter hair food debris: The second layer of activated carbon is used to remove scale and purify water quality The third layer of PP cotton to remove odor and improve taste: Inner and outer filter cotton: Specification: Name: Cat water fountain filter Inside material: Activated carbon, resin Size: Outer diameter: 127mm/5in,inner diameter:38mm/1.5in,thickness: 8mm/0.31in Package size: 13.2 * 6 * 13cm/ 5.20 * 2.36 * 5.12in Package weight: 65g Gift Box Packaging Package List: 4* Cat water fountain filter