Compatible with PetSafe Drinkwell Original, Platinum, Big Dog, Multi-Tier, Outdoor Dog, Mini, Everflow and Zen Pet Fountains. Our PetSafe Drinkwell branded filters contain 50% more carbon than the generic brands for longer lasting and overall better filtration. By keeping your pet hydrated, you and your pet can enjoy playtime more and live happy together. The PetSafe Drinkwell Premium Replacement Carbon Filter is compatible with PetSafe Drinkwell Original, Platinum, Big Dog, Multi-Tier, Outdoor Dog, Mini, Everflow and Zen Pet Fountains. This 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 more appealing to drink. Filters help extend the life of your fountain and pump and should be replaced every 2 to 4 weeks.