Pro Gear Crew SocksSeriously warm Surprisingly soft We created a sock from Bison down and silk that will keep your feet warm and dry all winter long. When summer comes, don't worry, they will also provide dry cool comfort in hot environments, with superior moisture regain properties, and exceptional air flow almost double the wicking of fine wool. (keeps your feet dry and sweat free) Exceptionally durable for outdoor activities, long distance running, hold up strong for