Features: 1.Two?way quick insertion, no air leakage, the air tube is connected to the air tube, and the air tube is connected to the diffuser. 2.6mm/0.2in outer diameter acrylic tube, stainless steel tube, trachea can be used. 3.Input from one direction, the air circulates; input from the opposite direction, the air does not circulate, ensures that the pressure on the output side does not change. 4.The working pressure is 0.15?1.0MPa (150psi), and the maximum pressure resistance is 1.5MPa. Insert for metric pipe (pipe outer diameter 6mm). 5.Adopt quality metal material, high strength, durable, long life time. Specification: Item type: Metal Direct Connection Pipe Material: metal Color: As picture shown Length: Approx. 4.5cm/1.8in Diameter: Approx. 1cm/0.4in Weight: Approx. 20g Product use: anti-return check valve PackageList: 1 x Metal Direct Connection Pipe Note： 1. This product is suitable for 4x6 air tube, the air tube should be hard, too soft and easy to collapse. 2. This product is compatible with most diffusers.