This is a unique Jaquet-Droz implementation of the World Time Watch. Jumping Hour with a
change of city by a single push-button:
J-Droz calibre 3663-4 based on the Piguet ebauche, 72 hour power reserve, jumping hour
display, timezone indication on a disc carrying the names of twelve cities.
Jumping hour at 12 o'clock, name of city at six with large minute hands, to change the city,
push the button at 2 o'clock and the correct time will show automatically.