The Wmns UltraBoost 'Ash Green' shoe features a flexible Primeknit upper that is reinforced by a caged Three-Stripes lacing system in the middle of the foot. To offer enhanced comfort and responsiveness, adidas introduced its groundbreaking Boost technology at a global event in NYC back in 2012. Boost is a state-of-the-art cushioning system that utilizes an advanced TPU material developed in collaboration with German chemical producer BASF. This innovative technology surpasses earlier designs by providing a higher level of energy return, resulting in a more energetic and springy feel.