The Chromatic Harmonica can be used for many different types of music. The main advantage that a Chromatic Harmonica has is its capability of producing extra notes by means of a slide button on its side. The slide is pushed to activate the chromatic notes, which closes off the airflow from one set of reeds and enables the other set to vibrate. A key of C chromatic is the most popular as it is like a Piano, sticking to one layout, so you can work out where all the notes are and go on to learn how to play in any key on that same instrument. Eventually with lots of experience and plenty of practice you will be able to work out how to transpose a tune into the key you want to play in without having to reach for another harmonica. However, if you enjoy playing chords or prefer a particular key, you may consider the other chromatics available.