The Nike React Infinity Run Flyknit 4 is an all-round running shoe. The shoe offers the soft, stable feel combined with a smooth ride that provides support during every long and short round. Flyknit has been added to the upper, creating zones that focus on optimal ventilation, flexibility and containment. The result is a feeling of freshness that helps keep your foot securely in place as you move without restriction. The Flyknit tongue is adjustable and soft, so your ankle and heel don't suffer from the lingering irritation of longer runs. The shoe is still equipped with Flywire technology for support around the midfoot. Even more cushioning has been added to the collar for a soft, protected feel. The midsole is equipped with Nike React foam. Nike React is a light, durable foam for a smooth, responsive ride. The foam is shaped like the base of a rocking chair. For example, it offers support for the three phases of settlement during running. It offers flexibility when your foot lifts off the ground, a smooth feel when your foot moves forward, and cushioning when you touch the ground. The wide shape provides a more stable experience and releases energy with every step. Less material between the sockliner and midsole means you're closer to the foam. And that means a more responsive experience. The foam itself is higher, for a soft feel. Extra rubber has been added to the outsole for increased durability and grip. As a result, you experience good grip and traction on both dry and wet road surfaces. The curved outsole also contains a rocker, which ensures that every step feels more natural and offers efficiency during your run. This in turn ensures that you waste less energy.