Compatibility: Cat Fountain Replacement Carbon Filters are compatible with 1/2 Gallon, 1 Gallon, 2 Gallon, Butterfly, Avalon, Pagoda, Seascape, Sedona, Seaside and Creekside Pet Fountains; Three-layer Filtration: This replacement filter consists of a cotton layer, activated carbon. It removes hair, debris, odors and other impurities so that the water always tastes fresh and clean; Pre-filter Sponges: Sponge can prevent debris from clogging and damaging the pump, extending its working life; Change the Filter Regularly: Please soak the filter in water for 5 minutes before use and rinse thoroughly under running water. Replace the cat water dispenser filter once in 4 weeks in summer and once in 4-6 weeks in winter to ensure clean drinking water. More frequent changes if more than one pet is using the water fountain; WHAT YOU WILL GET: Included 6 packs of replacement filters and 6 packs of foam. Please contact us first and we will help you ASAP when you encounter some problems;