Bandoneon

  The bandoneón is a type of concertina particularly popular in Argentina and Uruguay. It plays an essential role in the orquesta típica, the tango orchestra. The bandoneón, called bandonion by a German instrument dealer, Heinrich Band (1821–1860), was originally intended as an instrument for religious music and the popular music of the day, in contrast to its predecessor, the German concertina (or Konzertina), considered to be a folk instrument by some modern authors. German sailors and Italian seasonal workers and emigrants brought the instrument with them to Argentina in the late 19th century, where it was incorporated into the local music, such as tango.

Bandoneon

Copied from: http://en.wikipedia.org/wiki/Bandone%C3%B3n