Adidas Ultra Boost Running Shoes step in to these running shoes and you'll rethink everything you know about what fast and comfortable feels like. They're built with boost? for incredible energy-returning cushioning beneath your feet without adding weight or sacrificing ground feel. These shoes feature a breathable Primeknit upper for a flexible and supportive fit. With a STRETCHWEB outsole that enhances the energy returning properties of boost?. Boost?'s energy-returning properties keep every step charged with an endless supply of light, fast energy. Adidas Primeknit is carefully engineered to naturally expand with your foot while you run to deliver a more comfortable fit and help reduce irritation; Engineered mesh upper with various types of mesh. Bootee construction for comfortable fit; Featherweight sockliner adapts to the foot for customized fit and feel; TORSION? SYSTEM for midfoot integrity. Highly elastic, snug-fitting heel with external heel counter for natural Achilles movement, stability and comfort.STRETCHWEB rubber outsole is lightweight and elastic, adapting to the ground for stability and working strategically to optimize the unique properties of boost? from touchdown to push-off.