Experience comfort even in cold winter weather with Lenz' patented Toe Cap® technology. Its low-profile heating element, sewn right in, ensures complete cosiness for your toes for a span of up to 14 hours. The elasticity of the Lenz Heated Sock 5.1 ensures an optimal fit in the calf area, even for those with athletic calves. The comfort cuff also ensures that the sock remains securely in place. Additionally, an integrated shin protector and protective toe and heel areas provide extra cushioning and protection.The secure fit of the Lenz Heated Sock 5.1 is ensured by a ring bandage. Constructed from a luxurious blend of merino wool, silk and functional fibers, this sock efficiently wicks away moisture and dries quickly. The rechargeable lithium pack attaches to the sock cuff with snaps, and the temperature can be regulated with the free Lenz heat app or directly on the lithium pack. The Lenz Heated Sock 5.1 is compatible with all lithium packs of the Lenz Body Heat System.