Keep the fresh, clean water flowing for your furry friend with Drinkwell Foam Replacement Pre-Filters. Designed specifically to fit Drinkwell's Lotus, Avalon, Pagoda, Sedona and 360 Stainless Steel pet water fountains, these foam pre-filters surround the pump housing to trap hair, debris and other large particulates for an added layer of safety and filtration. Pre-filters help maintain optimum flow rate, enhance the filtration ability of the separate carbon filter, and further prolong the life of your pump. The easy-to-install pre-filter fits easily around the pump inside the water reservoir and lasts up to two months.