Features of the Smartwool PhD Run Ultra Light Print Crew Sock Indestructawool Technology for enhanced durability 4 Degree elite Fit system for a dialed, Performance-oriented Fit Shred Shield Technology reduces wear from toes Body mapped mesh zones for added breathability Virtually Seamless toe for enhanced comfort Fabric Details 46% Merino Wool, 49% Nylon, 4% Elastane, 1% Polyester