Choosing a frame is actually choosing the material of the frame. Common ones on eyeglass mart include sheet metal, TR90 (plastic titanium), alloys, titanium, and so on.   The board has high hardness, good gloss, and is not easily deformed; Ti-P/Ti-C: Ti is an identifier for materials containing titanium, where Ti-P represents pure titanium, Ti-C represents titanium alloys, and so on. The...