M. Hohner 1920s German "Super Chromonica" Harmonica in Original Box, Key of GI don't know a lot about harmonicas, but upon spotting this one on a recent outing I found it so beautiful, and its box too, that I couldn't walk away. I've since learned it's quite a fine one, and, after sanitizing it, played it a bit, and indeed the sound is marvelous. This 12 hole chromonic harmonica in the key of G features a sliding piece (at right), which redirects air from the hole in the mouthpiece, producing the same scale a semitone higher