The Ultra Boost is comprised of a engineered mesh upper known as Prime Knit allowing the foot flex freely whilst in motion. With its' bootee construction adding additional comfort, the plastic 3-Stripe cages featured on the medial and lateral panels provide stability. The central section of the external heel clip has been cut out to allow the achilles to move correctly. adidas have increased the percentage of Boost to the silhouette which now sits at the forefront of the shoe where the EVA sole was on older generations of the Boost line. An energy harnessing Stretch Web outsole has been added - this adapts and stretches to the movement of your foot. Available now at selected retailers such a Footpatrol.