They are also the first socks we started with and are always our best sellers. Our mainstay, these Cozy Winter Warm Socks are made of Merino wool and Angora. Which is the lightest natural fiber known. The hollow structure of its fiber makes it ideal for thermal clothing and has been found to be 8 times warmer than sheep’s wool. This added warmth is wonderful for the outdoorsman and sportsman. Here in Minnesota we know the need for that added warmth.