The Nike Reactx a nod to the air suspension Technology similar to the Nike Shock. Size 13M The Nike ReactX takes Nike's React foam technology to the next generation, delivering greater energy return and a lighter feel than ever before. Designed for runners and lifestyle wearers alike, the ReactX midsole provides a bouncy, responsive ride that makes long days on your feet feel surprisingly effortless. Modern design meets cutting-edge comfort in this standout pair.