Invented a bit later than the accordion by British scientist Charles Wheatstone (in 1844), concertinas were considered for use in classical music and some composers actually wrote suites and sonatas for concertina in the 19th century.

They are smaller than either the chromatic or diatonic accordion and often have a hexagonal shape with buttons alternating between one side and the other. Their extreme portability made them popular with traveling musicians.

Concertina's in general do not have chord buttons like a standard accordion and fall into 2 categories.

1. Anglo Concertinas: These resemble diatonic accordions in that the tones stick to one key.
2. English Concertinas: These are fully chromatic instruments, capable of playing in any key.