Minute Repeater

Aimlessly browsing through Rediff.com I came across a slide show of the world's most expensive watches. And a feature that they all had was Minute Repeater. Naturally curious, I went and looked this up in the Wiki and this is what I found.

A repeater is a complication in a mechanical watch or clock that audibly chimes the hours and often minutes at the press of a button. There are many types of repeater, from the simple repeater which merely strikes the number of hours, to the minute repeater which chimes the time down to the minute, using separate tones for hours, quarter hours, and minutes. They originated before widespread artificial illumination, to allow the time to be determined in the dark,^[1] and were also used by the visually impaired.

Here are two examples -