This product is constructed to help protect your feet from the damaging effects of impact (heavy foot strike) on hard court surfaces, as well as shear and blistering common in tennis players. Exclusive THORLON construction wicks moisture better. Thick cushioning in the ball/heel for maximum blister, impact and shear protection. Extended cushioning over toes for maximum protection during fast stops and starts. Flat knit at instep for better fit. 88% Thorlon Acrylic, 10% Stretch Nylon, 2% Spandex. Made in USA.