Lange 1 Tourbillon Perpetual Calendar - A Lange & Sohne
DESIGNED FOR PERPETUITY
The sophisticated calendar mechanism controls the outsize date, day of the week, month, leap year, moon phase and the day/night indicator. All calendar displays switch instantaneously. Until the year 2100, months with 28 to 31 days are correctly displayed. Then, according to the rules of the Gregorian calendar, the leap day is skipped. The tourbillon, which can be halted with the patented stop-seconds mechanism in order to set the watch with one-second accuracy, assures the ultimate in precision.