(Pedantry) That's actually a chromatic harmonica, which is a somewhat different instrument from the diatonic harmonica / blues harp aspaviento is talking about.

(Pedantry) That's actually a chromatic harmonica, which is a somewhat different instrument from the diatonic harmonica / blues harp aspaviento is talking about. Chromatic harmonicas have a little lever that mechanically does some of the difficult tongue / breath stuff.