Nike InfinityRN 4 is a brand-new take on a familiar favorite. It's made from our all-new Nike ReactX foam, which gives you 13% more energy return compared with Nike React foam, to help you stay fresh and bouncy. (What's more? Nike ReactX reduces its carbon footprint in a pair of midsoles by at least 43% compared to Nike React foam.*) We coupled the ReactX foam with Nike Running's best-fitting Flyknit yet, so you can feel confident in every stride with soft upper support and breathability. It's the kind of