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 adapter is designed to refill small Argon or CO2 tanks from larger CO2 cylinders, allowing convenient and efficient tank 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 connector 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 top of the black adapter is in the highest position. Do not press down the adjustment knob during installation, as pressing the 6mm valve pin will close the valve and prevent CO2 from entering. 4. Reconnect the quick connector. 5. For most large cylinders, stand the cylinder upright or lay it horizontally, depending on internal dip 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 flow, which can be heard during operation. 7. After approximately 15–20 seconds, the cylinder will be fully filled. 8. Close the valve on the gas cylinder. 9. Open the bleed screw to release any remaining pressure. 10. Unscrew the CO2 adapter—refilling is complete. Color: Black Material: Metal Package Contents: 1 x Charging Valve Connector Note: Light reflection and different display settings may cause slight variations between the color shown in the image and the actual product. Measurement may vary by +/- 1–3 cm.