Heated Sox have been designed to keep your feet warm during the cold winter months. This value pack of 3 pairs have been tested to BS4745 standard, achieving a Tog rating of 2.13, considerably higher than normal thermal or cotton socks. A high tog rating provides extra insulation against low temperatures. They also feature reinforced heel and toe for extra durability, while not being bulky like other brands. These socks will keep your feet nice and toasty even in the polar extreme like temperatures, by creating pouches of warm air next to your skin, keeping your feet warmer for longer periods of time. Socks fit shoe sizes 8-12.5.