This heater uses a ruby crystal matrix to catylze the combustion products so that CO is not generated. If the ambient O2 level falls below 19.5% or so, then the unit senses this and extinguishes itself. In this sense, it is far safer than their other products. In fact, it is the only non-CO emitting propane heater I have found on the market.

I used mine with a 20 lb propane tank out hunting elk; first time in the back of my big suburban, with the window cracked. It was snowing and nasty at the time and still I got so hot with the thing cranked all the way down I had to kick off the sleeping bag and shut if off a time or two. The next year I towed my trailer up and used it in there and it kept up, but just barely, with a big storm that came in. I had ice on the windows on the inside, but I was warm enough not to be uncomfortable.

They are susceptible to fouling, and I found out the hard way that the oil that gets in a bulk tank can run up the line and get in the screen and then the thing is done for. If you are going to use bulk propane with it, you better have an oil trap in the line somewhere or it'll foul for sure.