The timbre of a guitar is determined by its body. Most people have never looked inside a guitar and may not realize it, but guitars are actually very cleverly designed. The guitar is a string instrument which is played by plucking the strings. The main parts of a guitar are the body, the fretboard, the headstock, and the strings. Guitars are usually made from wood or plastic. Their strings are made of steel or nylon. The guitar strings are plucked with the fingers and fingernails of the right hand or a small pick made of thin plastic. This type of pick is called a "plectrum" or guitar pick. The left-hand holds the neck of the guitar while the fingers pluck the strings. Different finger positions on the fretboard make different notes.