The patented Toe Cap (R) heating element guarantees all-round warmth and heats the toes from above and below. The heat sock 5.0 toe cap slim fit knee socks are ideal for narrow feet and legs. They are ergonomically knitted for an optimal fit and the ring bandage offers pleasant support on the foot. Shin protectors as well as further reinforcements at toe and heel prevent pressure points. The skin-friendly material mix of merino wool and silk is breathable, fast-drying and comfortable to wear. The lightweight rechargeable lithium pack battery is optional and sits barely noticeable under the special comfort cuff. Lithium battery packs must be purchased seperately. The heat can be controlled directly on the lithium pack or also via the free Lenz heat app on your smartphone. Lenz Heat Sock 5.1 Toe Cap Socks | Black | X-Small | Christy Sports