Giro advantage helmet the giro advantage helmet is the pros choice when they are racing against the clock it has been wind tunnel tested to ensure you can shave seconds off your times featuring giros super fit engineering and combined with the roc loc retention system make it look and feel like it was custom made for your head five front vents with exhausts channels leading to the rear will help keep your head cool super fit sizes s 51 55cm m 55 59cm l 59 63cm