cat fountain filter replacement - The uses coconut shell activated carbon. High-quality coconut shells are used as raw material. there are cationic components, which have the function of cleaning and activation. It can filter impurity water flow more evenly to obtain a higher quality water source. Efficient Triple Filtrations - Cat water fountain filters made of top qualityfilters and activated carbon, and an ion exchange resin. cat filters fountain can filter hair, heavy metals, and improve the taste of the water so that pets can drink clean and fresh water all day. ensure that every drop is healthy, making water more clean and fresh. Filter Frequency of Replacement - Each of the 6-pack cat water dispenser filters is individual so that each one will be fresh. We recommend changing them every 2 - 4 weeks to keep the water fresh and clean. If multiple pets use the water dispenser, more frequent changes will be required. Perfect Match - Filter Size is 5 * 5 inches, the diameter of inner circle is 1.45 inches. Compatible with YOUTHINK / ISYOUNG / PEDY / KOALAD/ HAPPYPAPA. Pet Fountain and fit for other same size of pet fountains as well, please double check the size before purchasing.