OTC Midweight with Cushion with Padded Shin and a Wool Blend. Over-The-Calf Height - The name says it all. The ultimate height for keeping the outside-out Composition - Knit with 53% Merino Wool 42% Nylon 5% Lycra Spandex. The fast action wicking pulls moisture away from skin, so no more sweaty, stinky socks. The soft, breathable merino wool has fast drying, all weather performance that keeps you cool in the summer and warm in the winter. Guaranteed for Life - If these socks wear, tear, or develop holes, Darn Tough will replace them. No strings. No conditions. Made in the USA with yarns from America and around the globe - Every pair of socks is knit in Vermont - the perfect testing ground for the finest premium all weather performance socks.