It's always seemed to us that few products more routinely fall short of their manufacturers' claims than biking sunglasses – one pair doesn't fit right, on another the lenses fog up. Or the so-called technological breakthrough actually detracts from performance: Recently, we tested a pair of highly touted polychromatic shades that we found nearly useless because the tint couldn't change anywhere near as fast as lighting conditions – when we hit a shady patch of road, we were riding blind. But the Assos Zegho sunglasses basically reset the game and justify the exorbitant price tag. The Zeghos are constructed from whatever space age materials popped out of the lab recently – par for the course with high-end bike gear – but where they really stand out is in the ingenuity of their design. First thing we noticed was the fit: balanced on the nose, but not resting on the brow, and so light (.97 ounces) that you might forget you even have them on. The lenses are equally astonishing – the top two-thirds are tinted, the bottom third is clear. When lighting conditions change, all it takes is a slight lift of the head to change your vision. Before we tried them, this didn't sound like that big of a deal. Within moments on the bike, we couldn't understand why anyone hadn't thought of this sooner. [$400–$470,]