After testing 400 combinations, Nike created React - innovative cushioning that's lightweight, durable and ultra-responsive. Built with a bootie-style, white Flyknit upper, the trainers mould to the contours of the foot, with a tongue that's seamlessly part of the upper to reduce pressure. They're sat on a React foam midsole, which is 13% bouncier than Lunarlon, responding to impact by instantly snapping back. For a lightweight finish, traction is only at the heel and toe - where's it's essential for push off. The runners are finished with a tonal Swoosh to the sidewalls.