When it comes to bike industry titans committing to large-scale product change, the track record has been good of late. When Campagnolo made the transition from their age-old square-taper bottom bracket/crankset interface to the Ultra-Torque design, it was to the extreme delight of cyclists across the globe. When Sidi phased out their beloved Ergo 1 to make room for the Ergo 2, it recalibrated our expectations for shoe comfort and fit to an unthinkably lofty place. And it's Giro's turn to astonish now, with the long-awaited unveiling of the Ionos helmet to replace their signature pro-quality helmet of the last the years, the Atmos.

Rumors about the Ionos have been in circulation since the 2006 Tour de France, when three powerhouse teams -- Discovery, Rabobank, and Phonak -- tested Giro's design throughout the entirety of the race. Their input must've been extensive, because Giro didn't release the Ionos for the '07 season as expected. Rather, they spent an additional year fine-tuning the design. Finally, for the 2008 season, they've unleashed it to the world.

What makes the Ionos so desirable? It boils down to a few key points: One is its weight. Giro makes liberal use of new lightweight composite materials to make the Ionos nearly 10% lighter than the vaunted Atmos. And then there's its ventilation. You get 21 huge vents -- in fact Giro states that they designed the structure of the Ionos around the vents, specifically to maximize head coolness. Giro calls it "Wind Tunnel Technology", and their testing indicates that you get 15% more airflow over your head in comparison to the Atmos.

The in-mold construction of the Ionos fuses the four-piece outer shell with its impact-absorbing EPS liner, allowing the two materials to reinforce each other for maximum safety. You can think of it as an super-strong exoskeleton, and it's bolstered by the composite sub-frame that runs throughout the helmet's liner and around the vents. This sub-frame provides structural support, impact-dispersion, and resistance to penetration. This complex structural design is the key to making the Ionos lighter, tougher, and more ventilated than any other helmet in the marketplace.

A RocLoc 4 and interior strap anchors allow you dial in the angles and pressure points for a perfect fit. Small fits heads 51-55cm, Medium fits size 55-59cm, Large fits 59-63cm. Available in 5 colors: Black/Carbon, Team Caisse d'Epargne Red/Black, Team Discovery Blue/Black, Crystal Blue/White, and Yellow/White.