All kinds of tonguing effects are also possible. Hohner Bass No. All the notes are blow, and have second reeds tuned an octave higher to give the note more bite. The Bass is actually two separate bodies, with one placed above the other, with the two held together by hinges on both sides, allowing you to angle the two mouthpieces in towards each other, or out away from each other. Well, the primary activity in most simple bass lines is to play the root and the fifth of the chord.
Most chords have perfect fifths.
It just happens that the C scale and the Gb scale in combination give you all the perfect 5ths on one row or the other. Both F and B are duplicated. This, of course, depends entirely on what you want to do. If you have a reasonable knowledge of music and you want to play Jazz or classical music, a chromatic harmonica is probably best. If you want to play blues or folk music or the likes, a diatonic is best.