Hohner Amatona IV button accordion (sold). This is the four voice ‘DeLuxe’ version of this classic instrument, tuned to BC, with five couplers to mix and match the LMMM reeds. As you can hear from the video it sounds fabulous and has a pronounced level of tremolo without being harsh on the ear.
[youtube=https://youtu.be/eyoIhS3P4qM&w=320&h=240]