Cold feet are the first thing to register at the top of a chairlift, and the Hotronic Surround Comfort Heat Socks Only keep the toe and ball of the foot heated in a thin sock. The surround heating element runs along the top and bottom of the foot, and the wool blend manages moisture. These heated socks come without batteries. What Our Gearhead(R) Experts Are Saying:"In my ski boots, the thin sock kept the fit snug, and the gentle compression stayed comfortable through a full day of turns. The reinforced toe and heel showed no wear at the end."