21 + 5 accidental treble buttons, 3 voices, 3 voices instrument with 5 automatic couplers, located behind the fingerboard, allowing 5 possible sounds :
- 1 voice : concertina (single medium reed)
- 2 voices : double medium reeds. (dry, swing or musette, according to voicing)
- 3 voices : double medium + single low octave reed
- 2 voices : Bandoneon.(single medium + single low octave reed)
- 1 voice : single low reed
12 basses with 3 stops.