1.Biochemical Filtration: with an air pump as the power source, combined with mechanical filtration, the principle of biological filtration utilizes multi-level filtration to produce good things, and the sponge filter for fish tank can absorb fine particles to achieve the effect of purifying water. The water flow is controlled by the airflow, which is small and slow and does not impact the fish. 2.Changeable filter material: two kinds of replaceable filter materials: sponge + ceramic filter balls. You can easily remove sponges from the filter for cleaning or replacement. It also has a media box with ceramic filters to help eliminate bad things and provide additional cleaning or use other filters media. 3.Easy to use: use an air hose to connect the end to the air pump and the other end to this tank filter. The outlet pipe in the sponge filter for fish tank can be adjusted so that you can change the direction and height of the water flow (not including the pump and air hose, please choose a powerful pump for this filter according to your tank size).