The Darn Tough Run ¼ Sock Ultra Lightweight with Cushion is a lightweight running sock with cushion underfoot, and protection around the ankle. The 1/4 crew height sock features fine gauge knitting and has fast action wicking that keeps moisture away. The all-weather performance sock is naturally antimicrobial and guaranteed for life. The merino wool provides breathability and comfort. The True Seamless™ offers an ultra-smooth and invisible feel. It comprises 50% merino wool, 45% nylon, and 5% lycra spandex.