Built-in double filtration, the safety filter works perfectly for clean water, keeping your pet healthier. Activated carbon has powerful adsorption function, remove impurities and odors, let your pets enjoy drinking water. PP cotton filters out coarse debris such as hair and scale. Efficient and durable, 1 filter will last you 2-3 weeks, but the point is to give your pet better access to clean water. It is recommended to do about 2 weeks, which can better purify the water, make it more refreshing, and provide delicious water for your dog or cat. EASY TO USE: This ceramic filter is easy to install on fountains. Please note that rinsing the filter with water before use can then clean the fine powder produced during transportation, making it clean and delicious, allowing your pets to enjoy drinking water. High Precision: Thanks to its unique design, this filter provides the best quality water for your dogs and cats. The activated carbon filter absorbs impurities to keep your fountain as clean as new. It is not necessary to clean the fountain frequently, which saves time and water. Wide Compatibility: This set includes 8 ceramic cat waterer filters that only connect to PetSafe Drinkwell, Avalon, Pagoda, Seascape, Sedona, and 8-Gallon fountains.