Memory foam adjusts for customized cushioning for the entire footPolyurethane layer for maximum cushioningAirflow channels provide cool circulationX Large fits U.S. Men’s sizes 11 – 12Medium fits U.S. Men’s sizes 6 – 8Large fits U.S. Men’s sizes 9 – 102X Large fits U.S. Men’s sizes 13 – 14Antimicrobial mesh covering to prevent odor-causing bacteriaOrthotic chassis provides arch support and heel stability