How does photochromic sunglasses work?

The lens change color according to the intensity of ultraviolet light in the sun, not sunshine. When the ultraviolet light is strong, the lens becomes deep grey and blocks ultraviolet rays. When the ultraviolet light is weak , the lens becomes bright, ensuring clear vision. Normal light, flashlight, car light, that do not include UV light, will not make the lens change color.

In dark tunnels, our photochromic and polarized lens is light color and no need take it off, safe to pass tunnel, but normal sunglasses lens have dark lens, the vision is unclear, not safe in tunnel.

When driving at night, the lens become bright, clear vision but also anti glare and high beam from other cars. Normal sunglasses lens can not see road clearly which will cause dangerous.

The temple material is titanium.

Unbreakable and light weight, no allergy to skin, use for long time.