This pack of 4 replacement charcoal filters are for the Drinkwell Avalon and Pagoda Ceramic Pet Water Fountains. Drinkwell Replacement Charcoal Filters keep your pet's water tasting clean and fresh. Each filter features a duo-density polyester pad that catches hair and debris, while the charcoal removes bad tastes and odours from the water making it more appealing to drink. Filters help extend the life of your fountain and pump and should be replaced every 2 to 4 weeks. Charcoal Filter removes bad tastes and odours Polyester pad captures debris and hair maintaining the Pet Fountain's cleanliness Constant circulation helps inhibit bacteria growth in between cleanings Filters extend the life of your Pet Fountain Replace filter every 2 - 4 weeks Compatibility Compatible with Drinkwell® Avalon, Pagoda & Sedona Fountains.