Hellion utilizes a lightweight, breathable, and durable asymmetrical upper built with Cordura ® that’s designed to keep you riding farther and charging harder. The PerformFitâ„¢ Wrap from the BOA ® Fit System is designed to improve power transfer and efficiency while providing a micro-adjustable, precision fit you can adjust on the fly. The asymmetrical collar provides additional protection on the inside of the ankle and the molded EVA midsole gives your foot a stable and efficient pedaling platform.