FLEXIBILITY DEFINED. Top to bottom the Women's Nike Flex 2016 RN Running Shoe is built to flex. Its one piece engineered mesh upper, co molded midsole and molded tri star outsole pattern work together for a smooth ride that moves with your stride.FEATURES Engineered mesh upper supports throughout your stride. Co molded midsole delivers a smooth ride. Tri star outsole design flexes as your run. Flywire cables offer a dynamic, supportive fit through the midfoot. Minimal heel design provides a more natural fit. Heel is rounded for a smooth transition at initial touch down.