On® Cloudswift 4 sneakers: Best for Running, Road running. The upper is made using a single piece of flat-knit engineered mesh. The breathable upper has a snug, sock-like fit that adapts to a wide range of foot shapes. Speedboard® Injection molded nylon-blend Speedboard for an energetic and responsive ride. The new dual-density midsole is made with two types of Helion™ superfoam - for soft landings and powerful take-offs.