88% THOR¿LON Acrylic, 10% stretch nylon, 2% spandex * Heavyweight padding protects feet against shock, impact and shear forces common to tennis * Size 11 (Medium) fits shoe 5.5-8.5; size 13 (Large) fits 9-12.5; size 15 (X-Large) fits 13-15 * Constructed of exclusive Thorlon Acrylic yarns which are specially spun to maintain both softness and resilience, maximizing foot comfort, blister protection and product durability * Wash and dry inside out (to fluff up the pads) using liquid fabric softener after each use (to lubricate the fibers for longer life). Liquid fabric softeners critical to receive full benefit of the product design