FITS Tracker OTC Socks are over the calf socks that stay snug against your leg and foot. No matter the harsh conditions these socks stay put and keep your feet warm and comfortable all day long. Nylon reinforced exteriorDoublt welted top: Keeps sock in placeCushioning surrounds ankle, calf, and whole footHeel lock for secure fit, helping to prevent blisters when worn with boots that fit properly. Dynamic Toe Cup contours to feet69% Super-fine Merino Wool/24% Nylon/4% polyester/3% LycraMerino Wool Fabric Tech: Moisture Wicking and Quick DryingBreathable and Temperature RegulatingOdor Resistant and AntimicrobialAnti-itchFlame Resistant