SockGuy's SGX socks are designed with the elite athlete in mind and features our exclusive Elite Performance Formula, a blend of polypropylene, nylon and spandex. The new SGX sock line provides a compression fit, performance ribbing, enhanced ventilation and a reduced friction profile. These socks feel great, look great, and with SockGuy's signature Stretch-to-Fit sizing and reinforced toe & heel, SGX socks perform like no other. Sizing: S/M: Men's 5-9, Women's 6-10, Euro 37-42, M/L: Men's 9-13, Women's 10-14, Euro 43-48