This item is a built-in filter that can be adsorbed on the wall of the fish tank. It uses en vironmentally-friendly sponge as filter material and can be connected with an air pump or a water pump to achieve the purpose of oxgenation and filtration an reduce the death of fish. Feature - Color: As shown. - Material: Plastic. - Size: 12x8x8cm. - The cylinder angle is arc-shaped to save space in the cylingder and the outlet angle is adjustable. - With multi-layer sponge filters, this corner filter combines physical and biochemical filtration for your fish and increases the oxygen solubility. - The layer of white filter pad serves a mechanical filtration, and the black bio-sponge and ceramic rings work as a biochemical filtration and support colonization of beneficial bacteria. - Quiet filtering system. Especially good for breeding small fish. Efficiently remove toxic waste and maintain clean water for your fish.