Plan and simple. IT WORKS. Its way better then basic thermals. Also, because it fits tighter on your skin it doesnt cause you to be as bulky in the woods. All my friends and family wear it when we hunt and in the dead of winter as long johns. Also, i know a ton of guides who use and swear by it as well. The cold gear is the way to go, and there is a difference between UA cold gear and the cheap stuff. Get the UA cold gear