This device allows you to connect 1L, 2L cylinders such as CO2, Mix cylinders to your existing aquarium fish CO2 tank regulator. Made of high-quality aluminum material, it is sturdy, durable, and offers a long service life. Compact and lightweight, it is easy to carry and store, and convenient to use. It connects to M10 gas cylinder to open and close the gas. Specification: Item type: CO2 cylinder adapter Model: M10X1 to W21.8-14 (DIN477) Note: W21.8-14 interface is only suitable for Europe, South Korea, Australia, and New Zealand. Material: Aluminum Color: Silver Package Contents: 1 x CO2 Cylinder Adapter Only the above package content is included; other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to appear slightly different from the real thing. The measurement allows an error of +/- 1-3cm.