The Darn Tough No Show Tab Ultra Light is an ultra-light running sock which weighs only 13 grams per sock. 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. This sock sits just above the ankle and has an undetectable seam fusion which gives ultra smooth, invisible feel. 51% Merino Wool 46% Nylon 3% Lycra® Spandex.