A chromatic harmonica is a harmonica, which redirects air from the hole in the mouthpiece to the selected reed-plate desired by using a button-activated sliding bar. It derives its name from the fact that its 12 holes long. The 12-hole harmonica is available in 12 keys. However, most professionals stick to C, which is the lowest note. The 12-hole chromatic harmonica has an ergonomically mouthpiece design and a precise and smooth slide mechanism. Since it has 12 holes, it can produce 48 sounds. The 12-hole harmonica comes in many different varieties such as the Harmon Angel 12.