With this device, you can connect 1L, 2L cylinders such as CO2, Argon, Mix cylinders to your existing aquarium fish CO2 tank regulator. Made of high quality aluminium material, sturdy, durable and long service life. Small and , easy to carry and store, convenient to use. : Connect 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. When placing an order, please be neutral and do not label. Material: aluminum colour: silver Package Contents: 1 x CO2 Cylinder Adapter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.