uahpet Filter Cat Fountain 6 Pack, Filter Drinking Fountain for Cats and Dogs, Cat Fountain Replacement Filters Circulating Filtration System with 6 Layers

["Filter Combo Pack - 6 Pieces","6-layer filter system in each filter, filter consisting of eco-friendly casing, KDF, ion exchange resin, quartz sand, coconut activated carbon, and cotton.","The 6x superior filter system provides cats with cleaner and healthier water. We recommend replacing the filter and filter sponge every 3-4 weeks."]