When breathability is paramount, Rex Air is the answer. Featuring a perforated upper for optimal ventilation, this boot combines all the features of Rex with a bonus. Every component of this running shoe has been designed to provide maximum protection. Worn by our Professional Pilots, Rex incorporates premium TPU protectors and fiberglass reinforced nylon exoskeleton for invaluable support. The high-density resin dial system is designed to provide a perfect fit while allowing you to adjust the boot from both sides. Strategically placed outside contact areas, it has been integrated into the boot structure to provide impact protection for safety. Non-slip side design for safe driving