This is a Tremolo 32 harmonica in the key of C.

Tremolo harmonicas are distinct by having two reeds per note. In a tremolo harmonica the two reeds are tuned slightly off a reference pitch, one a bit sharp and the other a bit flat. This gives a unique wavering or warbling sound created by the two reeds being not exactly in tune with each other.

Tremolo harmonicas are one of the most common forms of instrument used in folk music.