Bendable titanium is made of titanium alloy. It is also called memory titanium which can go back to its original shape even if you bend them anyway. However, yo can't break them. Pure titanium are more durable and lighter, but they are more expensive than bendable titanium.
Pure titanium contains over 99.9% of titanium. So they are lightweight ,corruption-resistant ,allergic-resistant and high intensity. Pure titanium frames are marked as Ti-P. While bendable titanium frames are marked as Ti-B.