Made from ISOLWOOL®-- a superior blend of 50% Merino WOOL and 50% polypropylene. This blend is 5 times the strength and durability of Merino wool alone. Shrink-resistant and itch-free our Wool socks will keep your feet drier and provide excellent insulation in all weather conditions. Sock Guys wool socks also feature their "Easy-Fit" cuff and "Stretch-to-Fit" sizing system for maximum fit and performance. Sock Guy wool socks out-wick and evaporate moisture better than any other wool sock on the market today.