Using the same midsole and outsole as the previous model, the Ultra Boost 20 continues to offer a plush, yet bouncy ride but the updated upper adds support and enhances comfort.What's NewUpper is more comfortable and supportiveCompared to the original Ultra Boost, the Ultra Boost 20 still contains 20% more Boost resulting in a softer and springier ride. To provide a smooth transition and add propulsion, the plastic torsion spring remains encapsulated within the midsole. Thanks to the addition of fibers stitched strategically to the upper along the sides of your foot, you can expect a better lockdown and added durability from this model. Finally, the cage that surrounds your midfoot was also softened to amplify comfort.