Our lenses are 1.5 mm polycarbonate, a highly resistant material but the major drawback is that it is susceptible to scratches.
Be aware that even if your lenses are scratched, the UV protection is not reduced, the mirror effect is purely aesthetic.
The same goes for the colour of the sun lenses.
Whether they be grey, brown or coloured... you can choose your glasses according to your preferences, you will be protected regardless of the colour.