What is a sunglass clip? How to choose clip?

What is a sunglass clip? So-called sunglass clip, polarized sunglasses are specially designed for myopia group, has the function of anti dazzle light, uv protection. Clamping piece which is produced by the seven layers of different materials, each layer of the lens with various functions. Recommended reading: how much sunglass clip? Lenses polarization Angle and radian is based on the principle of precision optical design, a lens were handled by the original factory to strengthen, scratch resistance and not easy deformation, broken. Actually, no matter in movies or in real life, often can see some of the frames with a pair of sunglasses can turn on and clamping piece. When he went to the sun, as long as the sunglass clip down obscure myopic lens, sun protection purposes. Entered the room, as long as the sun glasses take off, has become a myopia glasses. How to choose sunglass clip? First of all, the lens and the size of the installation frame to match; Second, choose resistance to scratch resistant, not easy deformation and broken style. If it is polarized sunglasses clip also need observe polarization Angle and radian is based on the principle of precision optical design, it is advisable to wear feels comfortable. 吗? 吗?
related: sunglass clip