Tourbillon

In horology, a tourbillon is an addition to watch’s movement. Specifically to the mechanics of the escapement.
French-Swiss watchmaker Abraham-Louis Breguet developed the tourbillon around 1795 from an earlier idea by the English chronometer maker John Arnold.

By mounting the escapement and balance wheel in a rotating cage a tourbillons purpose is to counter the effects of gravity. By doing this its intended to improve the watch’s accuracy.

Tourbillons are often fitted to luxury watches mainly to demonstrate a watch companies technical skill and as a novel decorative feature. Tourbillons are always exposed.