Seems to be a bit of misinformation (and complaints) on this product if you search it on Google. I think an older version of this kit shipped without the adapter from other retailers. The tread type on the regulator itself is W22, which will NOT fit a North American standard CGA320 bottle (such as for beverage carbonation systems) with a valve such as https://www.reefsupplies.ca/online-store/5-lb.-CO2-Cylinder-Empty.html or a painball pin type bottle. To be clear it may thread, but will NOT seal correctly. However the INCLUDED adapter works on BOTH North American standard CGA320 bottles AND pin type paintball bottles (same thread, different point of seal and pin valve) . No additional adapter purchase is required. THIS IS A VERY NICE COMPLETE KIT. Kit also came with a check valve, which is not listed in the description. An additional adapter would be required to use disposable type CO2 bottles, but these are usually available where they are sold. I ran through two disposable 3.2 oz bottles while waiting for my 5 lb to be filled. This video shows it being installed without the adapter. I believe this installation is incorrect. It will thread and tighten but does not seal correctly! It looks like he has pressed the regulators stainless into the soft brass of the tank valve to achieve a seal instead of sealing on the intended gasket! You can see how many turns he has left on the valve, should only be 1, not 3, the post has bottomed out on valve. Not a long term solution! Adapter seals correctly on gasket. USE PROVIDED ADAPTER. https://www.youtube.com/watch?v=pWhiZcGEaks Anyway, highly recommend, but make sure you set it up correctly. Will likely purchase a second one.