The Basalt 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  StrongStrut® arch support provides arch support while eliminating blister causing slippage and our  FreeVent® 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, lifetime warranty.