adidas Ultraboost 21 Women's Running Shoes Core Black/White/Violet Tone : Unleash your energy in the adidas Ultraboost 21! This version takes all the original style elements and combines them with updated technology to provide comfort, support and energy return. Slip into a soft Primeknit upper to stay secure and comfortable during activities. Every stride on the Boost midsole leads a lively ride to move you forward. The Adidas LEP torsion system increases forefoot bending stiffness for a more responsive run. When it comes to comfort and energy return, the adidas Ultraboost 21 reigns supreme! What's New? 6% more Boost capsules in the midsole provides the perfect mix of energy return and comfort. Newly redesigned LEP torsion system provides runners with less flex in the forefoot and increased responsiveness. Who's it for? Neutral runners who crave a high-performance shoe that provides incredible responsiveness and ultimate comfort during short or long runs. Fashion enthusiasts looking to improve their street style with a cool, comfortable shoe for casual use. Shoe Technology Upper: Primeknit upper wraps around the foot for a snug fit that supports movement. Made with recycled Primeblue material that contains at least 50% Parley Ocean Plastic for sustainability. Midsole: Responsive Boost cushioning unleashes incredible energy return. LEP torsion system gives runners less flex in the forefoot for more responsiveness. Outsole: Stretchweb outsole flexes naturally for an energized ride. Continental(TM) Rubber offers superior traction on wet and slick surfaces.