SmartWool Men's PhD Outdoor Light Crew Socks 77% Merino Wool, 22% Nylon, 1% Elastane Knit in USA of Imported Yarn 4-Degree Fit System for all day performance fit WOW Technology in High Density Impact Zones to reduce shock & abrasion Smartwool inside for moisture, temperature and odor control. Strategic mesh zones for maximum ventilation Duroyarn reinforcement for added comfort & durability