A ballpoint pen, also known as a biro, ball pen, or dot pen, is a pen that dispenses ink over a hard ball rolling in its point. The materials commonly used are steel, brass, or tungsten carbide. The design was conceived and developed as a cleaner and more reliable alternative to dip pens and fountain pens, and it is now the world's most-used writing instrument; millions are manufactured and sold daily. It has influenced art and graphic design and spawned an artwork genre.