Successor to the Ride EVERUNTM Topsole construction for enhanced energy return and continuous cushioning throughout the run PWRFOAM midsole Updated ISOFIT and all new FORMFIT technologies create a dynamic fit system by adapting to the shape and motion of the runner's foot Double jacquard mesh toebox provides structure or stretch where needed and enhances breathability Improved heel grab and lockdown Helpful for runners who suffer from underpronation, also known as supination. Check out this article about pronation to learn more