Thorlo Men's Experia CoolMax Micro Mini Crew Sock (Medium) 66% Coolmax/20% Nylon/13% Polyester/1% Elastic Specifically sculpted Thorlo padds in ball and heel provide protection from shear and impact Ultra lightweight sock frame of nylon and lycra provide aerodynamic contoured fit with mesh poly extra breathability Achillies Tendon Pad protects against rubbing and chafing Machine Wash