Most guitars have six strings, but there are also guitars with four, seven, eight, ten, or twelve strings. More strings make the instrument sound fuller. The neck of a guitar has bars or marks called frets. Frets help a guitarist know where to put his or her fingers to get the right pitch when playing. Standard tuning defines the string pitches as E, A, D, G, B, and E, from lowest (low E2) to highest (high E4). Standard tuning is used by most guitarists, and frequently used tunings can be understood as variations on standard tuning.