1, callout "UV400": This means that sunglasses lenses for UV cutoff wavelength of 400nm, its spectral transmittance in the wavelength below 400nm is not greater than the maximum value of 2%.
2, label "UV", "ultraviolet": This means that sunglasses lenses to the cut-off wavelength of UV 380nm, its spectral transmittance in the wavelength below 380nm maximum value not greater than 2%;
3, mark "100%UV absorption": This means that sunglasses lenses on the absorption of ultraviolet rays with 100% function, that is, its average transmittance in the UV range not greater than 0.5%.
Sunglasses to meet the above requirements, is a real act of UV protection sunglasses.
For normal consumers, it is difficult to distinguish sunglasses features by the eye, at this time, understand the optical identifications are a very necessary thing. Here is several common sunglasses identifies.