Designed to meet the demands of ultra-runners, this shoe has both the cushioning we need to go the distance and the traction and stability required for rugged terrain. In addition to a beefier midsole that attenuates shock and delivers comfort for all-day races, this shoe's got several stabilizing features for the trail, including an inner rock plate and PU inserts in the midsole. Meanwhile, high-traction rubber on the outsole keeps your footing secure on steep mountain trails. Customer feedback suggests this shoe runs small, we would suggest sizing up if you are unused to a tight performance fit.