Sounds are produced from the strings in a number of ways. The most common form of playing is called fingerstyle, in which the player plucks the fingers upwards with the ends of the fingers. It is common to use the index and middle fingers as the plucking fingers, but players may use more fingers or even employ their thumb to pluck downwards. Other finger-based techniques include slap-and-pop, in which the player strikes the lower-pitched strings firmly with their thumb, and pulls higher-pitched strings upwards and lets them snap against the fretboard, and tapping, in which the player hammers downward with their fingertips on the fretboard.