Updated fit and extra ease FluidRide midsole FlyteFoam bottom layer midsole FluidFit 2.0 mesh upper Designed with multiple levels of cushioning, combining the FluidRide midsole, RlyteFoam bottom layer, and Speva Foam top layer, the Gel-Nimbus 20 delivers the perfect level of bounce-back and support at every stride. The cushioning also decreases midsole breakdown, while the FluidFit 2.0 mesh upper adapts to your feet and offers superb breathability. Finally, gel cushioning at the rear and front of the foot provides unrivalled comfort when you need it most.