Please check your tank thread before placing an order. OD: 22mm W21.8-14 / DIN477 / M22-14 for your large 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 CO2 tanks from larger tanks, allowing you to conveniently refill small cylinders. CO2 Refilling Station Charging Adapter Type: W21.8-14 How it works: To use correctly, please 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 (ensure the knob on top of the black adapter is in the highest position; do not turn the adapter knob down to open the cylinder. If the adjusting rod lowers by 6mm and presses the valve pin, the valve will close and CO2 cannot enter). 4. Connect the quick connector. 5. For most large cylinders: turn the large cylinder upside down or lay it down (some main tanks do not have a dip/syphon tube inside). 6. Carefully open the valve of the large gas bottle (the valve on the cylinder closes the flow if opened too much. This occurs if the large cylinder is opened too quickly. The key is to open it slowly. You should hear the airflow for successful filling). 7. After approximately 1520 seconds, the cylinder is fully filled. 8. Close the valve of the large gas bottle. 9. Open the bleed screw to release residual gas. 10. Unscrew the CO2 cylinder filling complete. Color: Black Material: Metal Package Contents: 1 x Charging Valve Connector Note: Only the items listed above are included; other products are not included. Light reflection and different display settings may cause slight variations in the color of the item shown in the picture.