PetSafe Drinkwell Charcoal Carbon Filter, 4pkPAC00 13906 The PetSafe Drinkwell Replacement Carbon Filters are compatible with the PetSafe Drinkwell 1 2 Gallon 1 Gallon 2 Gallon Avalon Pagoda Sedona and Seascape pet fountains. These filters keep your pet s water tasting clean and fresh. The activated carbon made from coconut shells removes bad tastes and odors from the water making it more appealing for your best friend to drink. It is recommended that you replace the carbon filter every 2 to 4