The GEL-Nimbus 21 delivers the best ride yet with the introduction of Adaptive GEL, which offers more cushioning as you fatigue. Updated FluidRide creates a more responsive ride in a lighter weight packaging and a 360 Fluid skin upper adapts to your foot while strategic overlays seamlessly wrap and support your feet throughout the run. IMPROVED UPPER FIT. Gradient Mesh in combination with 3D print will provide an excellent fit combining the right amount of flex and support. A different lasting method will provide more room in the toe-area. IMPROVE FIT WITH NEW EYE-STAY DESIGN. The star-shape makes the eye-stay more deformable, which improves static and dynamic fit.