Great condition. gum stain bottom sole. Get excited for every run in the Mach 4. Inspired by the propulsive speed of the Rocket X and Carbon X, the Mach 4 employs a harmonious blend of foams – merging an incredibly soft, lightweight foam on top with rubberized foam directly beneath BEST FOR: Everyday Run Race FEATURES: Engineered mesh Anatomical Achilles construction PROFLY™ construction Early stage Meta-Rocker Rubberized EVA outsole Molded EVA sockline