Fluval AquaClear 20 Media Maintenance Kit includes all three types of replacement media for the AquaClear 20 filter, making routine maintenance straightforward. The kit contains a foam sponge insert for trapping debris, an activated carbon insert for chemical filtration, and a BioMax ceramic ring insert for biological filtration. Replacing these ensures the filter continues running efficiently – keeping the water clear, removing toxins, and supporting beneficial bacteria in your aquarium.