In addition to the comments earlier about the value and suitability of the Pro Grip shields, I want to make certain that all understand that these DO NOT become dark, dark, dark! The colored reflective ones certainly seem much darker from the outside looking in, but don't expect to be able to ride into late afternoon/setting sun without the "squints"

Purchased these (all colors + "clear") with the idea that I wouldn't have to worry about changing shields on the road, as well as not having to buy prescription sunglasses. I can say without hesitation that the colored shields look terrific (while not as opaque as "mirrored" shield for those of you who prefer the intimidation factor.) The colored shields seem to have little if any "light sensitivity" to them. Doesn't seem to have made a difference where or when, or what type of lighting conditions, they just don't seem to do much (actually, that's a better term than "not doing anything") One other downside to these shields: due to the space between the helmet shield and the surface of the Pro Grip (due to very rugged and well made gasket/adhesive) night-time riding brings on multiple reflections as the light sort of bounces along between the surfaces. At least that's been my experience with the colored shields. I've not even mounted the "clear" one as of yet, as the instructions recommend waiting 24 hours prior to use, and by the time I think of it, it's usually much less time than that to ride! An alternative to changing shields to some extent, until I take a significant ride along a dark country highway, I can't say they're the best alternative.