adidas Ultra Boost ST running shoes feature the first-ever multi-density boost™ which delivers incredible stability in a progressive manner. That system allows the foot to work more naturally when you run. Plus, this midsole is made with 100% boost™. The design includes a sleek profile and bold color.Upper: Seamless Primeknit forefoot comfortably stretches to hold the foot in place while reducing irritation and increasing ventilation. Midfoot tongue wraps around the foot to provide dynamic arch support and superior fit. Midsole: Full-foot boost™ midsole provides unmatched energy return and superior cushioning. S-curve Achilles system provides dynamic heel fit that works together with the boost™ foam to adapt at touchdown.Outsole: Continental Rubber Stretchweb outsole is specifically engineered to adapt to all surfaces and support key traction zones.