This helmet is CPSC compliant evolution of Giros famed advantage model, and it was developed with countless wind tunnel hours and the feedback of several elite riders over the last 3 years.
The Advantage 2 is truly a top-level race product. In wind tunnel testing sessions with Lance Armstrong and other elite riders, the Advantage 2s performance was benchmarked against rival designs and Giros own aerodynamic fairings (helmets that had no impact-absorbing foam liner). The results show that this design produced remarkably similar drag numbers to previous designs, and is among the dated of all the designs tested.
(Taken from Giros website)