Coolmax / mesh polyester fiber maximizes breathability to keep feet cooler. * Ultra-lightweight sock frame provides a contoured, aerodynamic glove-like fit. * Sculpted Thorlos pads in the heel and ball offer protection from impact. * 66% Coolmax, 20% nylon, 13% polyester, 1% elastic. * Made in USA. Care: Machine wash with lukewarm water, inside out. Tumble dry low. Liquid fabric softener recommended.