I have one and it works great, had it for going on 4-years. The instructions said to put the cylinder in a deep freeze for 45-min before trying to refill it. I do this and I can get them refilled 100% as much as a new cylinder. One time alter freezing and refilling a cylinder I put it back in the freezer to lat it get cold again and then filled it some more. It worked so well that the cylinder bulged out some when it got warm. That was the last time I did that. It’s best to fill them from a big tank that is no less then ¼ full, after the big tank get ¾ empty it doesn’t fill the small cylinders so well.

I bought the refill adaptor for $13.00 at Harbor Tools.