Just because the sun goes down or the weather gets cloudy doesn't mean you don't still need eye protection. Optic Nerve's Squeezebox Sunglasses have easily switchable lenses so that you're never straining to see, and you always know what's going on. It's like 2 pairs of shades for the price of one. The smoke colored lenses defend against the bright sunlight...but if that goes down, pop the copper lenses on and watch the scape light up with amazing definition.
Smoke lenses protect against sun and glare
Copper lenses protect your eyes and keep view brilliant in less-than-sunny conditions
Ventilated lenses help keep fog from building up
Adjustable nose piece gives you a customized fit
Tough, durable lenses can stand up to some rigorous abuse