The tango accordion is variety of accordion, very popular in Argentina for use in playing tangos and related music.
It uses buttons for both left and right hands, unlike the piano accordion, which has a piano-style keyboard for the right hand.
It is also called a bandoneon or a concertina. It has a big range of nearly 5 octaves.
It is a bellows driven free reed instrument , or a "squeezebox". The instrument was developed in Germany
from the middle of the nineteenth century. The bass buttons play single notes rather than chords as on some accordions.