Multi-stage filtration promotes a healthy aquatic environment for Nano, Betta, Breeder Tanks, and Beginner Aquariums. The Mini-Bubble Filter includes mechanical sponge with activated carbon chamber. Biological Gravel media for beneficial bacteria growth. Removes debris in water for a healthy aquarium. Air Operated, Circulates Water, Suction Cups secure installation. Easy to use and replace Filter Sponge and Carbon cartridge.