Feature Lens material: TAC Frame material: memory metal Transmittance classification: 3 categories / sunshade mirror Whether polarized: yes Glasses structure: full frame The Benefit of Sunglasses Ultraviolet rays can damage the cornea and retina, and sunglasses can eliminate UV radiation when the eye receives too much light it naturally shrinks the iris once the iris shrinks to its limit then people need to squint. If the light is still too much such as the sunlight reflected from the snow it will damage the retina sunglasses can reduce the regulatory burden of the ciliary muscle of the glasses in the bright light. Tips Never clean your sunglasses with paper towels or clothing, which can leave scratches. Just use clean water and included a cloth to clean it. Never leave your sunglasses under the car's front window, especially in summer. Prolonged exposure to the oven-like temperatures inside a car can degrade the lens. Please don't put your sunglasses in your purse without a protective case. Because the inside of a bag is often filled with the key or other loose objects, which will cause the sunglasses damage.