Softness and stability combine in the Puma ForeverRun NITRO® Knit. Stay centered during your run. The ForeverRun NITRO has firm density guide rails that keep your foot aligned, perfect for those who need a little extra stability or overpronate. The nitrogen-injected foam gives you maximum cushioning, softness and bounce, so you feel like you can run forever in comfort. Details Upper: Engineered knit upper with Puma’s PWRTAPE that has targeted reinforcements for support and durability. There is an asymmetrical heel counter for an easy step-in and to help prevent irritation. Midsole: NITROFOAM™ is an advanced nitrogen-injected foam that provides responsiveness and cushion in a lightweight package. Stability: Puma’s RUNGUIDE SYSTEM features a firm density guide rail that keeps your foot aligned and centered throughout your stride. The PWRTAPE upper also provides additional stability with targeted upper reinforcement. Outsole: PUMAGRIP, a durable performance rubber compound that is designed for all-surface traction. There is a flared rubber outsole to help disperse your energy.