A ballpoint pen, also known as a "biro" and "ball pen", is a pen that dispenses ink over a metal ball at its point, i.e. over a "ball point". The metal commonly used is steel, brass, or tungsten carbide. It was conceived and developed as a cleaner and more reliable alternative to quill and fountain pens, and it is now the world's most-used writing instrument: millions are manufactured and sold daily.