Snugpak Antarctic Sleeping Mat- OD GreenIn freezing weather, self inflating, rubber based mats often crack when rolled, and valves can freeze. The Antarctic mat uses only sleeping bag insulation to prevent heat loss, so no need to worry about anything cracking or freezing. The layer of sleeping bag insulation prevents convective heat loss between your body and the ground. Any perspiration that is wicked away from your sleeping bag will also wick through to the bottom of the mat, leaving