In addition to the vitality of the lens in sunglasses, the quality of the frame is also an important factor affecting the quality of the sunglasses. Usually a good frame is comfortable to wear, does not affect the skin, and will not loose or skid when worn for a long time. The inferior frame is the opposite. The choice of frame when picking sunglasses is also critical. First of all, regarding the metal sunglasses frame, we should pay attention to whether there is crack in the solder joint, whether it is strong or not; use a nail to look at the paint surface without scratches; for the sheet metal frame, carefully observe its surface Whether there are plastic particles, whether there are scratches, whether it is rough or not, whether the frame is distorted, etc.