Repeaters are those watches with an attachment added that will sound the time at the wish of the user.
The repeating mechanism is operated by either a slide, plunger or button in the case of the watch.

There are basically five types of repeating mechanisms, some more common than others:

Quarter Repeaters

The quarter repeater strikes the previous hour and quarter hour.

Half-Quarter Repeaters

These strike the hours, followed by the quarters also an additional single blow to denote the passing of an additional 7 1/2 minutes. These
type of repeaters are uncommon.

Five-Minute Repeaters

Five-Minute repeaters fall into two types. One system is similar to the half-quarter repeater but follows the 1/4 "ting-tang" by a single
higher - pitched strike for each 5 minute interval elapsed since the last quarter. The other system strikes the hours on a deep gong
and follows this with a single higher note for each five minutes period after the hour, omitting a 1/4 striking.

Minute Repeaters

The most complicated of the repeater is similar to quarter - repeater with the addition of the minutes. The minute repeater strikes the last
recorded hour, quarter and minutes.

Clock Watches

The clock watch is essentially a repeater with the features of a striking clock.