A harmonica that is fitted with slide button, which activates internal valves. The valves route air from one set of reeds (tuned to the “natural” notes) to another set of reeds (tuned to the “chromatic” or sharp/flat notes). This allows all 12 tones of the Western scale to be accessed. Chromatic harmonicas are most often used for classical and jazz styles of music, though some rock, blues, and folk players also use them. A chromatic harmonica can be used for any key, unlike most harmonicas, which are configured to play only a specific key’s pitches.