Built to keep you comfortable and keep you running, the fit offers roomy toe boxes and a zero drop Altra EGO? MAX midsoles give you light and luxurious performance with a little extra bounce and added durability According to Vibram, the sticky, high-performance Megagrip rubber offers rugged longevity, optimal ground adaptability, and unparalleled grip on both wet and dry surfaces GaiterTrap? hook-and-loop tabs allow the shoes to attach to Altra strapless gaiters (not included) Standard FootShape? fit?the most common fit from Altra, right in the middle of Original and Slim Altra recommends sizing up by a half size for more volume, or if you are in between sizes This product received the American Podiatric Medical Association (APMA) Seal of Acceptance, awarded to products found by the Association to promote good foot health