The term 'Harmonica Parts' can refer to the various components that make up a harmonica. The most important part of a harmonica is the reeds, which are thin metal strips that vibrate when air is blown through them. The reeds are held in place by a comb, which is a flat piece of plastic or wood with slots for the reeds. The comb also serves as a mouthpiece. Other parts of a harmonica include the cover plates, which protect the reeds from damage, and the casing, which holds all the parts together.