Abus GameChanger 2.0 Helmet S 51 - 55cm Flip Flop PurplePushing faster forward Through CFD simulations, wind tunnel and track tests comes the evolution of GameChanger. A true mastery of aerodynamics, without a gram of comfort or safety sacrificed. Multi position design for optimal aerodynamics regardless of the angle of the head Unique Aero Blade structure on top accelerates windflow and adapts to different speeds and inclinations of the head Rear AirFlow Star, w enlarged outlet area 32% boosted airflow