COMPATIBLE WITH: PetSafe Drinkwell Avalon and Pagoda Pet Fountains, 7.5 - 3.7 - 1.8 Liters, Stream/Sea ECONOMIC: Set of 4 filters with replacement charcoal ELIMINATES BAD TASTE AND ODOR: Thanks to the action of charcoal, the water is fresher for your pet. CONSTANT CIRCULATION: Allows bacterial growth to be slowed between cleanings EXTENDED LIFE OF YOUR FOUNTAIN: It is recommended to replace the filter every 2 to 4 weeks. Dimensions (L x W x H): 5.08 x 6.1 x 3.6 cm