I tried the Icebreaker boot blankets this week during deer rifle season opener in VA. I've been very impressed. I was wearing thin leather shoes (neither insulated nor waterproof) with a thin wool sock on opening day, and I had no idea that my hunting party was going to walk to some deer stands behind a cow field. It has been a wet one in this part of VA this season, so we ended up traipsing through mud and puddles in the early morning dark in the 30's. Normally, I'd be concerned, as sitting with wet, muddy feet in that kind of weather for hours and hours is generally not a good idea. When I got to my stands, I threw the boot blankets on and threw a Hot Hands packet on top of my shoe in each boot. My feet stayed warm, despite my shoes being wet and despite the low temperatures. Very good. I think these are a good option to expensive boots.