Whether you have flat feet or just need a little more cushion the Kenetrek Cushion Insole is just what you need to feel a big difference. Kenetrek started by adding extra high impact zone padding to the wicking, anti-microbial pad. And to guarantee your boots stay scent free, they utilized state of the art activated carbon technology. By setting the top high impact zone layer over a 4mm high density moldable foam, you'll barely notice the rockiest trails you follow.Size:Medium: 7 - 8-1/2Large: 9 - 10-1/2XL: 11 - 12 2XL: 13 - 14