Features: Circulating filtration purifies water quality, effectively removing fine impurities and harmful substances in the water. Multi-layer filter cotton design, rapid bacteria cultivation, improving filtration efficiency. High dissolved oxygen bubbles are delicate, the oxygen pump has large power, and it will not block after long-term use. The ecological filter cotton has a honeycomb structure, good water permeability, and strong filtration. The water outlet can be stretched and rotated, and the direction can be rotated 360, adapting to different use environments. Specifications: Material: Cotton,plastic Style: large / small (optional) Large: hight 29-34cm adjustable Small: hight 22-24cm adjustable Package size: 29*19*7cm Package weight: 343g Package List: 1*Fish Tank Filter