Polyphonic harmonicas generally have 16 to 28 holes, with 24 holes being the most common. The polyphonic piano holes are divided into two rows, upper and lower. When playing, the upper and lower reeds in the same hole sound at the same time, producing a "tremolo". It is constructed as a comb, two reeds, and two covers.

1) Each hole needs to play two sounds, which is thicker and heavier.
2) The sound is crisp, loud and penetrating
3) The body of the piano is thin and can be played for many postures
4) More suitable for ethnic style

            