The Air-E-Ator , by DeFeet is designed to take full advantage of the wicking capabilities of CoolMax and the abrasion resistance of nylon. The result is a cool, comfortable, long-lasting sock, which has become the sock of choice among professional riders, both on the road and in the dirt. 60% CoolMax /30% LYCRA /10% nylon. S(4-7 1/2), M(7 1/2-9 1/2), L(9 1/2-11 1/2), XL(11 1/2-14). USA (North Carolina).