With the React Infinity 4, you'll be ready to hit the ground running and leave all your worries behind. It's equipped with soft, responsive React foam and updated with our most snug-fitting Flyknit. So you can take off anytime, anywhere without worrying about wear and tear. It's the kind of shoe that gives you the priceless feeling of being able to run longer, faster and further than ever before thanks to high foam stacks and an intuitive design that supports every step. Smooth and stable The rounded outsole provides a more natural feel and more efficiency when running. So you waste less energy while running. It provides flexibility when the foot lifts off the ground, a smooth ride when the foot moves forward and cushioning on contact with the ground. Optimal cushioning Nike React technology provides a soft, responsive ride with durable, lightweight foam. Stacked cushioning is placed directly underfoot so you're closer to the foam for a truly responsive feel. Support and breathability Flyknit in the upper provides breathability to keep your foot feeling secure without suffocating. A water-repellent lining in the toe area provides protection in bad weather. So you can keep going and won't be slowed down by the elements. The Flyknit tongue is adjustable and soft, so your ankle and heel won't get too irritated on longer runs. An integrated Flyknit fit band ensures an elastic, secure fit. The foam collar provides a soft, supportive feel. Reinforced rubber on the outsole provides traction and durability.