I'm very intrigued by these. But I'm still a little confused as to what they are or how they work. Is it basically a temperature regulator? How does it work? Also, does it only work for charcoal, or does it work for propane cookers also? I just got a new Master Forge propane unit from Lowe's. Haven't even assembled it yet. But if this thing keeps the heat consistent like an oven, I think I might like to try it out. I did a quick search on the site but couldn't find much on their basic function and info. Thanks for any help.