The Racer ST 2 is designed to support you in your quest to break tape or set a PR. Speed, cushioning and control come together in a lightweight package, with a Diagonal Rollbar (DRB®) on the medial side to control the rate and degree of pronation through the midstance phase, and HydroFlow® heel cushioning to dampen impact shock, stabilize the heel, and rebound on every stride. Durable High Performance Rubber (HPR) improves traction and durability. Ideal for tempo training and race distances of 5K to marathon... ***ONLY 2 PAIRS LEFT***