[Perfectly compatible] with HAPUP water fountains for cats and dogs. Encourage your pet to drink more water and stay healthy. [Quadruple filtration system] Each cat water filter features a separator foam pre-filter, a high-density porous cotton layer, high-quality activated carbon, and ion exchange resin. The cotton layer helps trap hair, sediment, and debris. Activated carbon helps reduce bacteria and chlorine odor. Ion exchange resin helps soften tap water and may contribute to urinary tract health. Ideal for supporting your cat's overall wellness. [Improved and more adequate material] The blue and white cat water fountain replacement filters are made from high-quality, non-toxic materials that are easy to handle and clean. Each filter is individually packaged to maintain freshness and performance. The filter cartridges have been upgraded for enhanced quantity and quality, delivering more effective water purification. [Replacement interval] To minimize loose particles, rinse the blue and white cat fountain filter under running water and soak for 10 minutes before first use. Clean the filter weekly as part of regular maintenance. Replace the filter every four weeks to ensure clean, fresh water. Always position the flat end facing upward for optimal performance. [Good deal and friendly service] This pack of 6 blue and white pet fountain filters offers great value and long-term use. If you have any questions or concerns about the filter, please for assistance.