Insulative neoprene sock, delivering warmth and protection while running and hiking in winter conditions. The EXTREME THERMO SOCK keeps the foot warm when the temperature is cold and underfoot conditions are wet, by trapping a thin layer of water between the neoprene and the skin. The water is naturally heated by the foot, keeping it warm whilst the neoprene acts as an insulative barrier against the cold. The ankle cuff is seam free, delivering a snug fit with zero-irritation.