Features of the Smartwool Women's PhD Outdoor Medium Pattern Crew Sock Indestructawool Technology for enhanced durability 4 Degree elite Fit system for a dialed, Performance-oriented Fit Body mapped mesh zones for added breathability Virtually Seamless toe for enhanced comfort Narrower heel and Slimmer Fit Fabric Details 57% Merino Wool, 41% Nylon, 2% Elastane