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, and other regions. This adapter is designed to refill small Argon or CO2 tanks from larger CO2 cylinders, enabling convenient and efficient refills. CO2 Refilling Station Charging Adapter Type: W21.8-14 How it works: 1. Cool the cylinder in the freezer for 1 hour. 2. Attach the CGA320/W21.8 connection to a commercial CO2 gas cylinder. 3. Disconnect the quick connector of the black adapter, then securely tighten the black adapter to the cylinder. Ensure the knob on the top of the black adapter is in the highest position. Do not press the knob down during installation, as pressing the adjustment rod may depress the 6mm valve pin, closing the valve and preventing CO2 flow. 4. Reconnect the quick connector. 5. For most large cylinders, stand the cylinder upright or lay it horizontally, depending on internal tube configuration. 6. Slowly and carefully open the valve on the gas cylinder. Opening too quickly may restrict flow. A controlled opening allows proper gas transfer; you should hear airflow during the process. 7. After approximately 15–20 seconds, the cylinder will be fully charged. 8. Close the valve on the gas cylinder. 9. Open the bleed screw to release any residual gas. 10. Unscrew the CO2 adapter—refilling is complete. Color: Black Material: Metal Package Contents: 1 x Charging Valve Connector Note: Light reflection and differences in display screens may cause slight variations between the color of the item in the image and the actual product. Measurement may vary by ±1–3 cm.