Eager to make a major new contribution to the history of this complication, the Vacheron Constantin master-watchmakers and engineers have sought to create a mechanical movement capable of indicating not only the full time zones, but also the partial ones, so as to reflect the exact temporal reality in the 37 time zones. 
The display consists of three dials: a sapphire dial with a unique day/night shading; a metal dial with a “Lambert projector” type map; and a metal chapter ring. 
40-hour power reserve, mechanical self-winding Calibre 2460WT drives displays of the hours, minutes, central seconds and World Time. 
It enables simultaneous read-off of the time in all regions of the world, along with the day/night indication provided by the central world map. 
All indications are adjusted via the crown, thus considerably simplifying the use of this highly technical watch.
Despite its complex construction principles, the new mechanical World Time movement is extremely user-friendly. 
The wearer chooses the reference time and places it opposite the black triangle at 6 o’clock. 
The time in the reference location can then be read off either by the hour hand, or by the 24-hour disc, while the time in the other 36 time zones is simultaneously readable
The cities shown in black represent the full time zones, while the cities in red indicate half-hour or quarter-hour zones.