Puma Magnify Nitro 2 This shoe has the thickest piece of NITRO foam in the entire RUN PUMA line-up. Simply put, you get more of the good stuff in a shoe that is designed for comfort while you run. Beyond the nitrogen-infused foam outsole, you get an engineered knit upper and a moulded heel collar. It's maintenance in all the right places. NITRO : Our innovative Nitrogen-infused foam technology is lightweight and provides explosive energy stride after stride. PUMAGRIP Outsole: Durable rubber compound that provides best-in-class multi-surface traction.