Compatibility: Dog water filter replacement is only suitable for 3L with filter/3.6L/4.6L/6L/8L automatic pet drinking fountain; we provide 12-month replacement and 24-hour support, please feel free to contact us. Triple filtration system: The dog drinking fountain filter has a 3-layer filtration system. High-density filter cotton can filter hair and sediment; activated carbon can remove chlorine and odor, keep minerals; ion exchange resin can filter heavy metals. Ensure health: This filter can block hair and impurities, keep water clean; filter heavy metals, remove chlorine and odor, soften hard water, improve the taste of water for pets. Drink healthy water and reduce the risk of urinary tract infection. Warm Tips: Our filters are packaged in thickened paper boxes, before replacing the filter, please soak and rinse the filter with tap water. Replacement frequency: In order to achieve the filtering effect, please replace the filter every 30-45 days, if you have multiple pets, please replace it more frequently. List: 4*Pet drinking fountain filter