Giro's ethereal new Prolight helmet is 60-120g lighter than most top-end lids, with an actual weight of just 181g for our medium-sized CPSC-certified US sample (European versions are even lighter).
While that may not sound like much of a difference on paper, it's very noticeable after a few hours on the road, and Giro make few sacrifices in getting there.
To help save weight, the Prolight does without an internal reinforcement skeleton, so the vents are downsized to maintain structural integrity.
Ventilation is far better than expected, though, thanks to extra-deep interior channeling that makes the most of whatever air is coming in by funneling it straight over the top of your head.
Total airflow admittedly feels a half step behind Giro's Ionos and Atmos models (and some top pros notably reverted back to the Ionos during the Prolight's introduction at this year's Tour de France) but that still puts the new helmet on par with – or even better than – flagship models from some other brands.
General comfort is beyond reproach. The pared-down Roc Loc SL retention system is shockingly minimal with just a pair of spindly supports on the sides and an elastic band joining the straps at the rear. But the end result is remarkably effective as it both holds the helmet on securely and practically disappears on your head. If anything, the softer materials are even more comfortable than usual for those with close-cropped hair.
While there's no conventional ratchet or dial out back, Giro do at least include a three-position anchor up front to help tweak the circumference if needed. Save for the tightness around the chin, the lightweight webbing is fixed but Giro have obviously done their homework here as we never felt the need to adjust the fore-aft position during testing. If strap fit around the ears has caused you issues in the past, it'll be best to try one on beforehand to make sure the fixed position will work.
The aesthetics are a bit more polarising. Some folks we polled liked the look but most said the smaller vents aren't what they're used to seeing on a high-end helmet and somehow the red, white and black graphics scheme on our particular tester doesn't quite look the part, either. Giro will offer the Prolight in four colour options so one might suit you better than the others.
Comfortable? Yes. Airy? Surprisingly so. Light? Undoubtedly. Good looking? Best for you to decide for yourself.