The concertina is a family of handheld bellows-driven free reed musical instruments developed in England and Germany in the early 19th century and produced today in many countries. Commonly called "squeezeboxes," the family includes the Anglo, English, and duet as well as the chemnitzer and the bandoneon. Although each type is known for particular repertoire, all are adaptable to many kinds of music. All types can play chords, and in particular the English and duet types are highly chromatic and capable of playing fluidly in any key.
Anglo concertinas are frequently used for Irish traditional music and Morris dance music.
English concertinas are used for the above music types, but also have considerable 19th century classical repertoire.
Duet concertinas are used for a wide variety of musical styles. The Hayden duet is a recently developed style of this instrument.
Bandoneons are popular in Argentina and are often used for playing tangos.
Chemnitzer concertinas are often used for playing Central Eurpoean polka music.