Among the date display functions of replica watches, the perpetual calendar is the most advanced and complex mechanism. A perpetual calendar replica watch can tell the time accurately decades later if it is powered on continuously. This is different from the almanac clock, which needs to be adjusted every first day of March.
However, this mechanism still cannot really guarantee absolute accuracy. It counts the year 2100, 2200 or 2300 as a leap year when in reality it is an ordinary year. To make it easier to understand, a year that is full hundred (divisible by 4) but not divisible by 400 is still an ordinary year, not a leap year.
For the same reason, a more advanced version of the perpetual calendar function was born. The mechanism can precisely time the 400-year cycle, which means it counts years divisible by 4, but not leap years. Calendar mechanisms also become more complex due to the need to calculate time intervals ranging from very small (seconds) to very large (hundreds of years).
Perpetual calendar mechanisms have been around for a long time, pocket replica watches with this feature have been around since 1762. In 1925, Patek Philippe released the first wristwatch with this function. This year, they did something even more special in 1989 - on the occasion of the brand's 150th anniversary.
This special feature is a collection of 4 pocket replica watches called Caliber 89. These chronographs have a very special perpetual replica uhren calendar mechanism capable of counting exactly 400 years throughout the cycle.