Features: 1.Made of high quality stainless steel material, sturdy and durable, the diffuser is not easy to remove. 2.Exquisite craft, smooth and bright surface to provide a beautiful appearance for fish tank. 3.U?shaped design, easy to install and use to save much space. 4.Good effect, with the scientific design, the diffuser has the high and best CO2 dissolve rate. 5.There are several specifications for option, you can choose the suitable one according to your demands. Specification: Condition: 100% Brand New_x000D_ Item Type: Fish Tank Refiner_x000D_ Material: 304 Stainless Steel_x000D_ Color: As Pictures Shown_x000D_ External Diameter: Approx. 32mm/1.26inch_x000D_ Hole Diameter: Approx. 19mm/0.75inch_x000D_ Optional Length: Approx. 7cm/2.76inch, 25cm/9.84inch, 30cm/11.81inch, 35cm/13.78inch, 40cm/15.75inch PackageList: 1 x Stainless Steel Aquarium Refiner1 xHose2 xSuction Cup Note Note: _x000D_ 1. this product cannot be used in salt water tank_x000D_ _x000D_ 2. Using Instructions:_x000D_ _x000D_ Tighten when installing the refiner. Use of the new atomization will produce a large bubble, 24 hours after the disappearance_x000D_ 3. 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.