Heated Sox thermal socks. The socks are designed to keep feet warm in cold temperatures, rated for as low as -25°C (-13°F). They have a TOG rating of 2.13, which indicates their thermal insulation. The socks are made from a blend of materials, including high-bulk acrylic yarn. They feature a brushed inside for comfort and a reinforced heel and toe for durability. The packaging indicates they fit sock size 9-11 and shoe size 5-11.