The Giro Advantage 2 Time Trial Cycling Helmet is the time trial helmet of choice for champion cyclists like Lance Armstrong, Alberto Contador, Levi Leipheimer, Dave Zabriskie, and David Millar. Wind tunnel testing proves why it is so popular — Advantage 2 represents the pinnacle of aerodynamic performance, fit, and ventilation. When every thousandth of a second counts, this is the perfect helmet. With Giro's Wind Tunnel™ ventilation system, which combines active vents with internal exhaust channels, this helmet will circulate fresh air to your head and allow stale air to escape. The Advantage 2 also features Roc Loc 5, which is a groundbreaking fit system that allows you to easily dial-in both fit tension and adjust vertical position with a single hand.