Excellent Filtering System - The carbon filter is made of cotton, coconut shell activated carbon, and ion exchange resin, which can effectively filter hair and impurities in the water, allowing cats to drink fresher water. Easy Installation - Soak the filter in a clean container for 5 minutes. The filter must be fully soaked before use; otherwise, the water cannot disperse through the filter. (The water in which the filter element is soaked is colorless or yellow, this is normal.) Super Long Service Life - The cat fountain system will automatically prompt filter replacement, at least 300 hours (orange light on, prompting to replace the filter), or consider replacing a new filter according to the current filter status.