The Hohner Student III has 25 keys and 24 stradella bass, running from A to Ab, with maj, min and fundamental buttons. This would be a good accordion for someone who wants a lightweight but serious instrument, or for a learner. When restored (as this one was) these instruments make a marvellous sound because of their old reeds, which are mounted in zinc plates (modern reeds are normally mounted in aluminium plates). Please see the video demo.
[youtube=https://youtu.be/_rvI4bZm96o&w=320&h=240]