Giro Synthe Bike Helmet - Blue/Matte Black Large An unparalleled blend of aerodynamics, ventilation, and fit Wind tunnel testing shows that the Synthe is nearly as efficient as the fastest time trial helmets The Roc Loc Air fit system allows for adjustment of tension and fore-aft tiLT with one hand Elaborate internal channeling and massive vents boost cooling power Weighs only 250 grams