SmartWool Men's PhD Outdoor Light Pattern Crew Socks 62% Merino Wool 36% Nylon 2% Elastane Built for Performance in the Highest Degree, Uses two elastics for greater stretch and recovery to keep the sock in place, Patented ReliaWool technology in high impact areas provides superior durability, Patented ReliaWool technology in high impact areas provides superior durability. Strategically placed mesh ventilation zones provide ventilation for temperature and moisture management Flat knit durable toe seam, Sock Height: Crew, 8.5" overall height Knit in USA of Imported Yarn: 63% Merino Wool, 34% Nylon, 3% Elastane Style: SW0SW219