A demo done at the Hohner Museum in Trossingen, Germany. The comb with reeds riveted on is attached to the work bench, which has holes attached to an air source. The holes are operated by foot pedals, so any combination (pair) of reeds can be sounded. The reed to be tuned is supported by a metal strip, and the reed is filed, at the tip to sharpen, at the base to flatten. Thirds and sixths are tuned just: the harmonica is diatonic.