Aquapro 12 Platium Charcoal Water Filter Replacement for Drinkwell Pet Fountain 12 Packs premium charcoal water filters replace drinkwell water filters Keep the water in your pet's Drinkwell fountain tasting fresh Replace filter every 2 to 4 weeks The premium filter segments the charcoal into 6-compartments reducing the settling of the charcoal and enhancing overall filtration. Each filter features a duo-density polyester pad that catches hair and debris, while the charcoal removes bad tastes and odors from the water making it more appealing to drink Fit models: Original, Big dog, Multi-tier, Platinum, Outdoor dog & Zen