This is a regulator pressure reducing valve that can be used with gas cylinders (Midbon) for draft beer. I was using it to make strong carbonated water. Includes: 6mm pressure-resistant tube conversion plug, micro coupler plug, PISCO ball valve, pressure-resistant tube (approx. 1m long), and the regulator body (maximum pressure 3.8). By making a 5mm hole in an empty carbonated beverage bottle cap and inserting a Nitto Kohki micro coupler socket (female thread type) and tightening it with an M5 nut, you can make your own carbonated water. *The above-mentioned bottle cap is not included. Neither the bottle nor the cap in the example image are included. You can find instructions for making this by searching the web, so if you want to make carbonated water, please try making it yourself, but at your own risk. Micro coupler sockets etc. can be purchased on Amazon. Of course, it can also be used for draft beer servers.