Today,the hottest metal frame material is titanium. They are undamaged and will remain the original shape even after you bend them hard.Titanium is a lightweight but extremely strong metal used to manufacture a wide variety of products from aircraft to golf clubs. Titanium frames may be composed of pure titanium or titanium alloys that contain small amounts of aluminum,vanadium,and other metals to increase its flexibility. Titanium frames are very durable and light. The strength of titanium allows manufacturers to fabricate frames with very thin designs. Titanium frames are also non corrosive and hypoallergenic, so they won't react with your skin.