Please check your tank thread before ordering. OD: 22mm W21.8-14 / DIN477 / M22-14 compatible with CO2 tanks 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 easy 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 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 6mm on the valve pin, it will close the valve and prevent CO2 from entering). 4. Connect the quick connector. 5. For most large cylinders: stand the cylinder upright or lay it down (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. Opening the large cylinder too quickly can cause this. Open the valve slowly and carefully. You will hear airflow when it is working properly). 7. After about 15–20 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—refilling is complete. Color: Black Material: Metal Package Contents: 1 x Charging Valve Connector Note: Only the above package content is included; other products are not. Light reflection and different display settings may cause slight color variations between the image and actual item. Measurement error allowance: +/- 1–3 cm.