Perfect compatibility Compatible with the HAPUP water fountain for cats and dogs. Encourage Your Pet to Drink More Water and Stay Healthy.Quadruple Filtration System Each cat water fountain filter is made of the separater foam pre-filter, high-density porous filter cotton layer cotton, high-grade activated carbon and ion-exchange resin . Cotton layer: filters hair, sediment and debris. Activated carbon: eliminates bacteria and chlorine odors. Ion exchange resin: softens tap water and helps prevent urinary tract diseases. Ideal for cat healthImproved and More Sufficient MaterialsThe blue and white replacement cat water fountain filters are made of high quality bulk filter material, which is non-toxic, visible, easy to use and clean. Each fountain filter material is stored in individual package and well reserved with the best effect The filter element is fully upgraded, the quantity and quality improved to improve the cleaning ability more effectively.Replacement Cycle To help prevent charcoal dust from escaping, please rinse the blue and white cat fountain filter thoroughly under running water before use, and soak for ten minutes. Clean the blue and white HAPUP cat fountain filter weekly. We recommend replacing the filter every four weeks to keep the water clean. Please put the flat face up to ensure the best filtrationBargain & Friendly Service It is a bargain to have these 8 blue and white pet fountain filters, which can ensure you a long-term use.