The best I could determine is that the buttons are used to adust the strings to different frets, just like your fingers do. I have not seen that set up on any pictures, so I guess itis after market, maybe for someone who had troble pushing the stirngs with there fingers. Kind of Zither like. Some of the strings are to the point that you can pick the stings, push the buttons and have it go chromatically up from the particular open note. I wonder about the act of kindness to go to all that work to make the keys so someone could enjoy the gift of music. I found a guitar repair man who also works on older sting insturments. Has a number of dulcimers. I was going to take it to him have it tuned, maybe so restringing. It needs at least one new one. It has some cracks, but he thinks it is sound enough to try to set up an play. Then I need to attempt to replace the keys in that row. I know what I want to do, the skill maybe lacking. Any way for $ 54.00 it will make a neat wall hanging at the very least, or at best, a neat new insturment to learn. I wonder how many times it has played the old German carol Silent Night.