Heat Sock 5.1 with Battery PackNever freeze again with patented Toe Cap technology. The flat, sewn in heating element is not bulky and provides all round warmth for the toes for up to 14 hours. The fit in the calf area is ideal thanks to the increased elasticity. The socks are thus also perfectly suitable for stronger calves and thanks to the comfort cuff nothing slips. The knee high heat sock 5. 1 toe cap has an integrated shin protector and protectors in the toe and heel area.