The No Show Runweight Merino Wool Sock is tailor made for runners. It has everything you need and nothing you don&';t. It starts with a premium quality merino wool (41%), knitted to a form fitting nylon (55%) core. Then we add zoned elastic support (4%) in key areas for optimal fit and performance. The Basalt is a no-show sock, designed with heel and tongue tabs that provide comfort and a barrier of protection between you and your shoes. Our StrongStrutA(R) arch support provides arch support while eliminating blister causing slippage and our FreeVentA(R) airflow design works to keep the your foot dry in the area it needs it most. Wool is naturally moisture-wicking and odor-resistant. USA-Made EASY WASH & CARE - Wash it normally with your clothes in a cold, unbleached cycle. For the best results, turn them inside out.