Heated Sox have been designed to keep your feet warm during the cold winter months. They 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. -2.3 TOG Rating keeps your feet warm to -13F -High bulk acrylic yarn. Reinforced heel & toe for extra durability. Brushed inside. -New treatment to keep your feet fresh & odor free. -Comfort toe seam to reduce abrasion & improve comfort. -Moisture control to keep feet dry. -Fits men's shoe size 6-13, sock size 10-13 -91% acrylic, 5% nylon, 3% polyester