Driving Force The lightweight, molded midsole is hollowed out under the forefoot, where 2 Zoom Air units are positioned. This allows the Zoom units to compress under the weight then expand and help return energy. Top-Down Control A molded hook-and-loop strap is made from flexible, durable TPU. It wraps over the lower laces to help reduce internal foot movement by harnessing you over the cushioning. Euro-Step Stability An external piece of lightweight, durable TPU is built into the outer-side midsole. It helps keep your foot stable over the footbed when making quick side-to-side directional changes. Traction to Run The computer-generated outsole has a pattern like a topographical map. It helps optimize ground contact for traction in multiple directions. Cutouts in the foam under the toe and heel help reduce overall weight. Molded grooves in the rubber outsole help the shoe flex.