SmartWool PhD Mountaineering Socks - Past Season 70% Merino Wool, 28% Nylon, 2% Elastane Made in USA of Imported Yarn 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, Minimal cushioning for maximum performance in close-fitting shoes Strategically placed mesh ventilation zones provide ventilation for temperature and moisture management Heavy cushion heel and toe for maximum comfort and protection in the highest impact areas of the sock Flat knit foot and leg with heavy duty yarns for maximum comfort and protection in low volume mountaineering boots Sock Height: Over the Calf, 14" overall height- Style: SW0SW048