The frame is extremely lightweight to the point where you forget you're wearing them. They are photochromic, ranging from transparent to "smoke," which is a dark gray, almost black. According to the manufacturer, it takes about 30 seconds to change from one end to the other, depending on the amount of light and temperature. However, I don't know under what conditions they measure all of this, but it is far from reality.

I regret spending my money on them. The transition takes at least 1 minute, up to 1.5 minutes. So, if you go outside in the sun wearing these glasses, wear a hat with a wide brim because for 1-1.5 minutes, it will be as if you're not wearing glasses at all. On sunny summer days, I have shed many tears because of the sun.

While driving a car, because my head is in the shade, they never darken satisfactorily unless you have the sun directly against you, in which case, no matter how much they darken, it will blind you badly.

I do not recommend them unless you don't need dark glasses and wear them in more "uniform" lighting conditions.

The two stars are for their lightweight and photochromic properties (for those who can tolerate them)