Changes

'''Tuners''' are the metal pieces in the headstock that secure the string ends and are used to tighten or loosen each string's tension, changing its pitch. Most modern guitars use ''machine heads'': the tuner consists of two parts linked together with gears. The part that holds the string is called a '''peg''' or '''post''' (formally it's called a ''capstan''). The part you turn is called the ''knob''.

Some tuners are '''lockingtuners''' tuners - they feature an additional screw or other means to clamp the string inside the tuning peg. This makes initially tuning a new string easier and prevents strings from slipping or rewinding differently after a whammy bar dive.