The NPET 050TP replacement filters are only compatible with the NPET 050TP cat water fountain. This set includes 6 high-quality filters to keep the water clean and fresh for your pets. The filters are easy to use, simply place them under running water and let them soak for 10 minutes before using. Each filter is designed with a powerful filtration function, using high-density and high-performance activated carbon, along with a white high-density filter structure for multiple filtrations. This helps maintain water quality, increase oxygen content, and keep your pets healthy. Remember to clean the filter once a week and replace it every 4 to 8 weeks. If more than one animal shares the fountain, it is recommended to clean the filter more frequently.