The Yamaha Harmonica Melocode NO.15M has the functionality of two harmonicas in one. The front side is a 15-hole single harmonica, and the back side allows you to play the major triads of C major, G major, and F major. It's useful for adding chords to a song, or for ensemble playing divided into melody and chord sections, improving your sense of tonality and harmony. For elementary school students, 15 holes