PetSafe Drinkwell Carbon Filters (3-Pack) - PAC00-13070Product Description Change every 2 4 weeks to maintain water freshness Drinkwell Premium Replacement Activated Carbon Filters keep your pet's water tasting clean and fresh. The premium filter segments the carbon into 6 compartments, reducing the settling of the carbon and enhancing overall filtration. Each filter features a duo density polyester pad that catches hair and debris, while the carbon removes bad tastes and odors from the water to make it