Features of the Smartwool PhD Ski Light Sock 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 Mesh ventilation zones designed specifically for male skiers provide optimum temperature regulation and moisture management Virtually seamless toe Made in USA