The Darn Tough No Show Tab Ultra Light is the ultimate in lightweight comfort. This lightweight running sock delivers cushioning just along the bottom of the foot. The sock pulls moisture away from skin and repels bacteria and odor. It is made of merino wool which ensures breathability and comfort in all conditions. The sock has an undetectable seam fusion which gives ultra smooth, invisible feel. 51% Merino Wool 46% Nylon 3% Lycra Spandex.