Ballpoint pen

A ballpoint pen (Hungarian: golyóstoll, also eponymously known in British English and Australian English as a biro and pronounced /ˈbaɪroÊŠ/ bye-roe in Britain and Australia but sometimes /ˈbiːroÊŠ/ bee-roh” elsewhere, named after its inventor László Bíró), is a modern writing instrument. A ballpoint pen has an internal chamber filled with a viscous ink that is dispensed at the tip during use by the rolling action of a small metal sphere (0.7 mm to 1.2 mm in diameter) of brass, steel or tungsten carbide. The ink dries almost immediately after contact with paper. Inexpensive, reliable and maintenance-free, the ballpoint has replaced the fountain pen as the most popular tool for everyday writing.