Please check your tank thread before ordering. OD: 22mm W21.8-14 / DIN477 / M22-14 of 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. CO2 Refilling Station Charging Adapter Type: W21.8-14. How it works: 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 (must turn the knob on the top of the black adapter to the highest position. The entire process does not require turning the adapter knob down to open the cylinder. If the adjusting rod presses down the 6mm wide valve pin, this will close the valve and prevent CO2 from entering). 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 closes the flow if opened too much. This occurs when the large cylinder is opened too far or too quickly. The key is to open it slowly and carefully. You will hear the airflow, indicating proper filling). 7. After approximately 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 cylinder — 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 display settings may cause slight variations in color. Measurement may vary by +/- 1–3 cm.