Features: Under Armour ColdGear Survival System Sock features UAs signature moisture wicking technology designed to help keep your body heat circulating. The Survival System is a sock combo consisting of a unique, fully cushioned boot and OTC that can also be worn independently on cool/cold days or together for maximum warmth. The boot sock features arch support and mesh vent channels for comfort and warmth. The lightweight OTC offers flat knit construction that reduces bulk and conforms to your foot. Fabric Tech: 67% Olefin / 32% Nylon / 1% spandex (OTC) 41% Olefin / 41% Wool / 17% Nylon / 1% spandex (Boot Sock) Color: Graphite (OTC) Black (Boot Sock)