After getting our hands on a Giro Aeon, we can officially declare this to be the marvel of cranial preservation and luxury that is has been purported to be. Weighing in at 219 grams, (medium, on our scales) the Aeon weighs a mere 24 grams more than the Prolight. However, there are several factors that will give the Aeon the edge for many riders.

Prolight's are still the only choice if you are counting grams and ride in an area with fewer climbs. What the Aeon brings to the table is a wider range of usability. Ventilation is on par with the air-conditioned Ionos, RocLoc 5 provides top-of-class adjustability and security, and the increased padding makes the Aeon as comfy as possible. Fit-wise, it's closer to an Ionos than an Atmos, which is on the bigger and rounder side of the fit range.

So, if you are looking for the one helmet that comes as close as possible to doing it all, the Giro Aeon is your choice.