Whether you want to train for a half marathon running on a treadmill or outdoors you'll find these supportive shoes really comfortable. Your feet and back will love these shoes. The third Generation. Fit: Fits true to size. Category: Stability or support. For people with flat feet or pronators. Best for: Intervals, tempo runs, recovery runs, short runs to marathons, heavier runners. Cushion level: High. The Materials. A midfoot stability tube combines support with a gentle, foot-hugging feel. The ultralight engineered mesh upper has a new airflow-optimizing pattern. Underfoot, Helion™ and CloudTec® combine for lightweight agility and heavy impact protection. The Technology. The next-gen Cloudflyer has the plushest tongue of any On shoe and some of our largest Cloud elements. With Helion™ superfoam, a bespoke Speedboard™, 3D-molded heel and a wider outsole, it's all about comfort and support. Slow and fast. Short and long. Heel and toe. However you run. The Design. Built for the graft nobody sees, but ready to step into the spotlight. The Cloudflyer is for the resilient. The strugglers. The overcomers. Those who stare adversity in the face and grin back. Because hard work pays off in the long run. And support makes light of any challenge.