The Darn Tough Vermont Men's Prism Crew Socks have ultra-lightweight Merino Wool's silky for great moisture-wicking. These durable and best-fitting socks have a True Seamless™ Toe that offers total comfortable bliss. They're knitted with thermoregulating wool fibers that hold and release heat depending on what the body is doing. Their bombproof durability extends up to the heels to deliver extra protection into the Achilles heel. The Darn Tough Vermont Men's Prism Crew Socks promises a manufacturer's lifetime warranty, uncompromised comfort, flexibility, durability, and fit in your daily activities or your workout time.