This is app which listens sounds via mic and displays notes with octaves. It is designed for Harmonica Key of C. It's very useful for beginners harmonica players because it shows notes during playing. But if you are planning another keys of harmo you should think about app: Harmonica Tuner PRO

Numbers from 1 to 10 present holes for blowing or drawing. Row above with notes presents note for blow, and row below - note for draw.
Other notes are obtained via bending.

Application works:
1. Listen for sound and in the right down corner show frequency and note with number of octaves
2. If sound is harmonica sound, then note is lighted in yellow color.
3. After buy Record feature you may recording and sharing you play as video