Before you step out of your tent after a cold, stormy night, switch out of your sleeping socks and into the SmartWool PhD Outdoor Heavy Over The Calf Sock to see what awaits outside your door. SmartWool’s signature hard-wearing wool, nylon, and elastane blend will regulate your temperature through harsh alpine conditions, while ensuring your feet can breathe when you start to work hard. Whether you’re shoveling the driveway or making a summit push, trust this plush over-the-calf sock to take care of your toes.