This Mountain Fly has been specifically designed to protect your feet from virtually all rough terrain. A GORE-TEX membrane in the upper provides breathability and offers the industry's greatest waterproofing. All other areas have been outfitted with durable hard rubber that provides unlimited protection. The same rubber surrounds the big toe for optimal all-around protection. Thick chevron lugs on the grippy outsole maximize grip and provide optimal strike. Flexible cuffs at the ankle prevent debris from entering, while reflective elements on the heel and laces ensure good visibility in the dark. The secret lies in the comfortable React midsole, where a carbon fiber plate, adopted from the advanced Vaporfly 4%, extends the entire length of the shoe. Its stiffness improves endurance and protects against hard, uneven surfaces.