The Nike Free 4.0 Flyknit is a top-notch running shoe specially remodeled to enhance competitive racing. Its 'Grey Volt' version presents a refreshed take on traditional design elements through the use of woven textiles featuring dual-tone fibers, printed Swoosh logos, and well-placed perforations that promote efficient airflow. The incorporation of Flywire cables ensures a personalized fit that adjusts to the wearer's movements, while the round heel design effectively prevents any slipping. Continuing to deliver incredible responsiveness and flexibility, this shoe stays true to its roots with the inclusion of a Phylon midsole and a durable rubber outsole.