It turns out one of the best ways to keep your feet warm in cold weather is to wrap them in mammal hair. And when it comes to mammal hair socks, they don't get much better than the DeFeet Woolie Boolie Knee High Socks. They're thick for extra warmth, they insulate even when wet or sweaty, and they're not even itchy. Knee high design gives more coverage and warmth in colder conditions. Wear these socks under tights for cycling, winter runs or skiing. When the days turn chilly, these are some of the best socks you can get.