Please check your tank thread before making an order. OD: 22mm W21.8-14 / DIN477 / M22-14 for your CO2 tank. Commonly used in Russia, Korea, Japan, UK, France, Switzerland, Sweden, Ukraine, Germany, South Africa, Czech Republic, Singapore, etc. This item is used to refill small Argon/CO2 tanks from larger CO2 cylinders, allowing convenient refilling of small tanks. CO2 Refilling Station Charging Adapter Type: W21.8-14 How it works: To use correctly, follow these instructions: 1. Cool the cylinder in the freezer for 1 hour. 2. Screw the CGA320/W21.8 connection to a commercial CO2 gas cylinder. 3. Disconnect the quick connector of the black adapter, then tighten the black adapter to the cylinder. (Turn the knob on the top of the black adapter to the highest position. Do not turn the adapter knob down to open the cylinder. If the adjusting rod presses down the 6mm wide valve pin, the valve will close and CO2 cannot enter.) 4. Connect the quick connector. 5. For most large cylinders: upright or lay the cylinder horizontally. (Some host tanks do not have a dip/syphon tube inside.) 6. Carefully open the valve of the gas bottle. (The valve on the cylinder may close the flow if opened too much. This occurs if the large cylinder is opened too much or too quickly. Open the valve slowly and carefully. You will hear airflow when it is correct.) 7. After approximately 1520 seconds, the cylinder is completely filled. 8. Close the valve of the gas bottle. 9. Open the bleed screw to release residual gas. 10. Unscrew the CO2 adapter filling is complete. Color: Black Material: Metal Package Contents: 1 x Charging Valve Connector 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 actual product. Measurement allowance: 13 cm.