【Scope of use】This cat water fountain filter is suitable for 81 oz/2.4 liter round cat water fountains. 【Product size】Outer diameter: 12.6 x12.6cm. Before purchasing, please make sure the size of this filter matches your pet's water fountain! 【Multiple filtration system】The activated carbon, ion exchange resin and cotton in this cat water fountain replacement part can effectively remove impurities, heavy metal ions and odors in the water, and filter out hair and fine debris, improve water quality, and let your pet love drinking water! 【Important tips】To avoid charcoal powder falling out of the water fountain filter, soak it in water for 3-5 minutes before replacing the filter to provide clean, fresh water for your beloved pet. 【Regular replacement】For the health of your beloved pet, we recommend replacing the pet water fountain filter every 2-4 weeks, and more frequently if you have multiple pets. 【You will get】6 cat water fountain filters. If you have any questions about the product,