PERFECT COMPATIBILITY: This fountain filter is suitable for 108 oz/3.2 L and 67 oz/2 L fountains and 84 oz/2.5 L stainless steel fountains. Fountain Filter: The cotton layer and activated carbon form a three-layer filter system. They filter hair, particles, heavy metals and improve the taste of drinking water. Regular Replacement: It is recommended to replace the filter water and sponge every 2 weeks for proper maintenance of the fountain. If you have more pets, change them more often. Easy to replace: The filter and sponge of the pet water bowl fountain are easy to remove and install. Tip: Before replacing the filter element, soak it in clean water for 5 minutes, then rinse it thoroughly with running water to keep the water clean and fresh.