ON RUNNING Cloudultra 2 Black / Sand. The Cloudultra 2, an all-terrain ultrarunning upper from the Swiss brand, is the perfect shoe for all outdoor adventures, urban or off-the-beaten-track, for short and long distances. Mesh sock upper for total support. Missiongrip™ rubber outsole for optimum grip. CloudTec® cushioning. FlipRelease system for a perfect fit.