Please check your tank thread before making an order. OD: 22mm W21.8-14 / DIN477 / M22-14 for your large CO2 tank. Common in: Russia, Korea, Japan, UK, France, Switzerland, Sweden, Ukraine, Germany, South Africa, Czech Republic, Singapore, etc. This item is used to refill your small CO2 tanks from your large tanks so that you can refill your small tanks easily. CO2 Refilling Station Charging Adapter Type: W21.8-14 How it works: In order to use it 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, and then tighten the black adapter to the cylinder (must turn the knob on the top of the black adapter to the highest position. The whole 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 CO2 cannot enter). 4. Connect the quick connector. 5. For most big cylinders: turn the big cylinder upside down or lie it down (some host 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 will happen if you open the big cylinder too much or too fast. The trick is to open the big cylinder very carefully. You will hear the airflow. This is necessary for successful filling). 7. After about 15–20 seconds, the cylinder is completely filled. 8. Close the valve of the large gas bottle. 9. Open the bleed screw to drain residual gas. 10. Unscrew the CO2 – done. Color: Black Material: Metal Package Contents: 1 × Charging Valve Connector Only the above package content is included; other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to be slightly different from the actual item. Measurement allowed error is +/- 1–3 cm.