Features: 1. Made from high quality copper and hose material, which is study and durable. 2. Round air bubble ring, ideal to increase oxygen content into the water. 3. Copper air inlet nozzle, convenient to connect air tube, simple to operate. 4. Not easy to move when placed it under the fish tank bottom. 5. It needs to be matched with a 20w above oxygen pump to use. Specification: Main Material: Copper and hose Color: As Pictures Shown Size Type: Single Ring Dia 15cm, Single Ring Dia 25cm(optional) Ring Dia: 15cm/5.9in, Ring Dia: 25cm/9.8in Round pipe diameter: 16mm/0.6in(suitable for connect inner dia 8mm/0.3in air tube). Package List: 1 x Air Bubble Ring 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.