Smartwool Mens PhD Outdoor Medium Crew 3-Pack Merino^Mesh^Nylon^Wool Made in USA You don't need a PhD to figure out what a class act these men's hiking socks from Smartwool&reg; are. Features a medium-cushioned outdoor sock ideal for light hiking, trail running and biking. Ribbed cuff with ankle band for comfort. Contoured Flex Zone on topside. 4-Degree Banded Fit System construction for performance fit. Arch band at upper and lower instep for support. WOW technology in High Density Impact Zones (forefoot/heel) to reduce shock and abrasion. Wool on Wool (WOW) technology adds an additional layer of 100% SmartWool&reg; Duroyarn&trade; to give the PhD sock line up to 30% more durability, performance and comfort. SmartWool&reg; infused for moisture, temperature and odor control. Duroyarn&trade; reinforcement for added comfort and durabilit