1、Mini size is ideal for small fish tank. 2、Can be also used as auxiliary filter for big size aquarium after linking with oxygen pump(Not included). 3、No need extra electricity, can be driven with an oxygen pump. Easy to split box and clean 4、Easy to split box and clean. 3 suction cups on the bottom. 5、Washable activated carbon and cotton. Features: Mini size is ideal for small fish tank. Can be also used as auxiliary filter for big size aquarium after linking with oxygen pump(Not included). No need extra electricity, can be driven with an oxygen pump. Easy to split box and clean. 3 suction cups on the bottom. Washable activated carbon and cotton. Functions: Activated Carbon: improve the water quality of the fish tank Cotton Filter: absorb the residual dirt, resolve fish feces quickly Quartz Sand: obstruct a large number of fine particles in water Increase the solubility of oxygen in the water Bubble stone ejection of clean air will lead to clean water How to use: Received a pump vent holes, directly into the fish tank apply Size: 8 x 8 x 8cm Package:1 x Mini Aquarium Filter Note: Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.