Description: This easy to use soda machine Cylinder Filling Adaptor will enable you to fill your own CO2 from your larger bulk cylinder into smaller SodaStream cylinders. An easy and inexpensive way to fill your own soda machine Cylinders at home at a fraction of the cost of getting the refills from your local store. Hose length: 50cm with reinforced spring cover. How it works: In order for you to use it correctly, please follow our instructions: 1.Cool the soda machine 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 soda machine cylinder( must turn the knob on the top of the black adapter to the highest position,the whole process does not need to turn the adapter knob down to open the sodastream cylinder,If the adjusting rod press down 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 tank has not the dip/syphon tube inside.) 6.Carefully Open the valve of the large gas bottle(The valve on the soda machine Cylinder closes the flow if it is opened to much. This will happen if you open the big cylinder too much / too fast. The trick is to open the big cylinder very carefully. You will hear the air flow. So to fill it successfull) 7.After about 15-20 sec., The cylinder is completely filled 8.Close valve of the large gas bottle 9.Opening the bleed screw to drain residual gas 10.Unscrew the CO2 cartridge – done Please note: The whole process does not need to turn the adapter knob down to open the soda machine cylinder If the big bottle is too big to be upside down, you can put it down to inflate