On Running's revolutionary Helion superfoam provides protection on impact and responsiveness on push off. Combined with the re-designed Speedboard that runs down the length of the shoe, the Helion foam really turns impact into acceleration. A new heel unit gives a better hold on the foot, better durability and comfort. The final new feature is an elastic strap on the tongue to tuck your laces into- a great addition! Overall this is a lightweight but cushioned shoe for training and racing.