I can personally say that the UnderArmor works. I was in Iraq last winter and wore it everday. The temperature in the winter is usually very cold plus the windchill. Anyway I was doughtful at first about UnderArmor but then got some sent to me. It works extremely well. Haven't got to hunt in it yet but it will be the first thing I put on this winter. I still like Doc's idea. Hunt from the truck!