Replacement filters compatible with the Vekonn 2.4L stainless steel top round cat fountain. 6-pack replacement filters. The diameter measures 5 inches. A replaceable charcoal filter removes dirt and food particles, as well as eliminating unpleasant odors and flavors. Please soak and rinse it with water thoroughly before being used. It is recommended to replace the filter every 2-4 weeks. Vekonn Cat Water Fountain 6 Filters Pack for Stainless Steel Top Fountain and Yellow Stamen Fountain