The PhD® Outdoor Light Crew Sock offers high durability on all your adventures with Indestructawool technology. Featuring mesh zones, a Virtually Seamless® toe, and the 4 Degree® elite fit system, this sock provides exceptional comfort. Indestructawool utilizes a proprietary yarn and construction method which strategically places Merino and reinforcement fibers where they are needed most. The result is the most durable and comfortable wool sock ever made. 4 Degree elite fit system uses two elastics for greater stretch and recovery to keep the sock in place Ventilation designed for end use: more mesh in Ultra Light and Light weights ensures maximum breathability, thermoregulation, and moisture management. Virtually seamless toe 8.5" overall height 56% Merino Wool, 41% Nylon, 3% Elastane Made in: USA