Please check your tank thread before placing an order. OD: 22mm W21.8-14 / DIN477 / M22-14 compatible with your CO2 tank. Commonly used in Russia, Korea, Japan, UK, France, Switzerland, Sweden, Ukraine, Germany, South Africa, Czech Republic, Singapore, etc. This item is designed to refill small Argon/CO2 tanks from larger CO2 cylinders, allowing convenient and easy refills. 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. 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 onto the cylinder. (Ensure the knob on top of the black adapter is turned to the highest position. Do not turn the adapter knob down during this step, as pressing the adjusting rod 6mm into the valve pin will close the valve and prevent CO2 flow.) 4. Reconnect the quick connector. 5. For most large cylinders: either stand upright or lay horizontally, depending on design. (Note: some source tanks do not have an internal dip/syphon tube.) 6. Carefully open the valve of the gas cylinder. (Opening too wide or too fast may cause the valve to close automatically due to backflow. Open slowly until a steady airflow is heard for successful filling.) 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 residual gas. 10. Unscrew the CO2 adapter — filling complete. Color: Black Material: Metal Package Contents: 1 x Charging Valve Connector Only the items listed above are included; other accessories are not part of this package. Note: Lighting effects and monitor settings may cause slight variations in color between the product image and actual item. Measurement error allowance is +/- 1–3 cm.