Style#: FZ4019-100 The more cushioning that you have underfoot, the softer and more comfortable your running experience can be. Cushioning helps soften impact as your feet hit the ground. ReactX foam gives you an incredibly smooth feeling, helping you push your limits. Waffle outsole provides durable traction. Flyknit tongue is adjustable and plush. Foam collar is soft and supportive to the touch. Increased rubber at the outsole gives traction and durability. A water-repellent liner in the toe helps keep you dry when the weather turns. This version of the Nike InfinityRN 4 still provides a plush and smooth ride, with the new ReactX foam delivering more support. The revamped Flyknit upper and wider toe box help your foot feel stable and secure.