As we know, the material of frames is very important for the wearer. Some kinds of materials are very lightweight. Such as: Nylon frames are a common material which is suitable for children, because they are hard to break. And Flexon frames are the good choice for the people who need flexible frames. If people want to wear a light frame, the titanium frames are the nice choice for them. Especially for people who have the sensitive skin. If you wear metal frame, the skin will appear many red measles. But using pure titanium frames, it is very comfortable and safety. Who knows how to discern the real pure titanium frames? Thanks.