A. Lange & Söhne - German watch, Wrist watch, mechanical movement, Glashutte, Chronograph, Tourbillon

ZERO RESET
Patented mechanism that simplifies the synchronisation of the watch with a time signal. When the crown is pulled, it automatically causes the seconds hand to jump to the 12 o'clock (zero) position.

Moon-phase display
A disc that rotates under the dial and is visible through an aperture. It shows the moon phases from full to new, generally as seen from the Northern Hemisphere.

Outsize date display
Depending on the size of the watch, this useful function makes it possible to display the date up to five times larger than in a conventional watch of similar dimensions. It is based on the patented two-disc mechanism.

Perpetual calendar
The calendar display of a mechanical watch is called "perpetual" if it automatically updates the date, the day of the week, the month, and the moon phase displays. It not only takes into account the different durations of the months in the course of a year but also "knows" which years are leap years. The complex mechanism is controlled by so-called cams.

It is the first self-winding wristwatch in the history of mechanical timekeeping that features a | perpetual calendar, an | outsize date, and a patented | ZERO RESET mechanism that allows the calendar displays as well as the | moon-phase indication to be advanced both individually and, with one single main push-piece, collectively.