A repeater watch is a complication watch that indicates the hours by means of striking gongs – a function activated by a pushpiece or slide.  There are several types of repeater watches:

• Quarter-Hour Repeaters – this type of mechanism is designed to strike the hours and quarter-hours.  A low-pitched gong is struck to indicate the hour, while quarter-hours are indicated by a low and high note truck together.
• Half-Quarter Repeaters – this type of mechanism is designed to strike the hours, quarter-hours and half-quarter hours, i.e. 7.5 minutes after the quarter-hour.  A low-pitched (bass) gong is struck to indicate the hour, quarter-hours being indicated by a combination of bass and treble notes, the first half of the quarter-hour by a single note and the second half by two treble notes.
• Five-minute Repeaters – these come in two versions:  a bass note is struck to indicate the hours, and a treble note for every five minutes, rather than for every quarter-hour.  A bass note is struck for the hours, combined bass and treble notes for the quarter-hours, and a treble note every five minutes in addition to the quarter-hour.
• Minute Repeaters – watches that strike or sound the hours and minutes on demand by activating a button.
• Grandes Sonneries – (GRAHND sohn er EE) – this mechanism is designed to strike the hours and quarter-hours en passant, i.e. automatically, in a way similar to the traditional pendulum clock.  A pushpiece, or a slide, makes it possible to select striking the hours, quarter-hours and minutes.