The On Cloudspark’s dual-density midsole and nylon blend Speedboard gives you a propulsive ride and high-energy return you can feel. What does that mean? It means less ground contact time and more air time. So you’ll feel like you’re flying over the pavement. Details: Upper: Light and breathable, the engineered mesh upper made from 100% recycled polyester molds to your foot with a shape and fit tailored to the needs of more runners. Plus, reflective details help keep you visible in low light. Midsole: The dual-density midsole and nylon blend Speedboard work together to give you an energetic ride and forward rolling sensation that adds a spark to your runs.Outsole: Rubber outsole for smooth grip and long-lasting durability.