The Lenz 6.1 Toe Cap Compression Unisex Heated Socks with rcB 1200 Batteries feature Toe Cap heat technology, compression knit and high merino wool content. Toe Cap provides warmth from both above and below the toes. The thin compression knit construction makes these socks geat for race boots and provides support to reduce fatigue during physical exertion. The high percentage of merino wool combined with technical fibers provides a pleasantly warm and dry feel while transporting sweat away from the feet. The included lightweight rechargable lithium pack battery sits barely noticeable under the special comfort cuff. Control the heat directly on the lithium pack or via the free Lenz heat app on your smartphone.