55% Nylon 40% Merino Wool 5% Lycra Spandex Made in the USA Ultra Lightweight - Our lightest sock for race day or anyone looking for a lighter-than-air feel from a tougher than hell sock. True Seamless technology allows for an undetectable seam fusion for an ultra-smooth, invisible feel. No Show Tab Height - The toughest sock you’ll never see. When your shoes are on this sock is gone. Composition - Knit with 55% Nylon 40% Merino Wool 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.