SmartWool PhD Nordic Ultra Light Socks - Past Season 53% Merino Wool, 42% Nylon, 5% Elastane Made in USA 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, Men's-specific mesh ventilation zones provide additional breathability and moisture management, Light cushioned shin and sole for impact absorption and warmth Strategically placed mesh ventilation zones provide ventilation for temperature and moisture management Sock Height: Crew, 8.5" overall height Virtually seamless toe Style: SW0SW011