🐠【Biochemical Filtration】 With air pump as the power source, combined with mechanical filtration, the principle of biological filtration utilizes multi-level filtration to culture beneficial nitrifying bacteria, and the sponge 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. | 🐠【Changeable filter material】Two kinds of replaceable filter materials: sponge + filter box. You can easily remove 2 sponges from the filter for cleaning or replacement, with a total of 4 sponges. It also has a media container with a ceramic filter inside to help eliminate harmful substances and provide additional cleaning power. Other filters can be replaced. | 🐠【Easy to use】 Use a 4mm air hose to connect one end to the air pump and the other end to this tank filter. The outlet pipe in the sponge filter 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). | 🐠【Upgrade filter】Aquarium filter can increase the amount of water dissolved, ultra-quiet, not easy to block, can be installed with filter material. Multi-layer design of filter cotton, with a large surface area, full filtration without dead ends. The suction cup is strong and secure. The bottom direction is 360 degrees rotatable. | 🐠【Suitable Size】 The medium sponge filter is 6.3 inch width and 9 inch to 13 inch height, the sponge inside circle diameter is 0.59 inch, suggest for 15 to 55 gallon fish tank. For larger tank you may need 2 of this filter. Suitable for shrimp tanks, betta fish tanks, breeding ponds, goldfish, juvenile fish or other fish.