SmartWool PhD Nordic Medium Socks - Past Season 66% Merino Wool, 32% 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, Medium cushioned shin and foot to protect against boot contact and ultimate warmth Strategically placed mesh ventilation zones provide ventilation for temperature and moisture management Sock Height: Crew, 8.5" overall height Flat knit durable toe seam Style: SW0SW013