Overview Crafted to be light and fast. Built with FuelCell foam to deliver maximum propulsion and speed with minimal weight. The FuelCell Rebel v4 will be your go-to shoe for any kind of run. FeaturesFuelCell foam delivers a propulsive feel to help drive you forward. More about the product FuelCell foam delivers a propulsive feel to help drive you forward. Sublimated graphics and no-sew overlays enhance durability and style. Weighs 212 grams (7.5 oz). Material: Synthetic/mesh upper.