What are the popular science we need to know about watches（3）?

Displays the watch's spring tension, similar to a car oil gauge. Long power watches are generally more than 72 hours, generally 7-10 days, and the longest is one month. Long-power watches have a large number of barrels or a very long mainspring. This function is more useful.

The perpetual calendar is one of the three major complex technologies in watches and clocks, and it has a very mature design in the ancient pocket watch era. The basic principle of realizing the perpetual calendar is to design a 48-month gear (also called a 48-tooth program gear) according to the 4-year 48-month cycle of a leap year. 

Commonly known as "Ghost Pushing Mill", the tourbillon watch represents the highest level of mechanical watch manufacturing technology. The entire escapement speed regulating mechanism is combined and can be rotated, continuously rotating at a certain speed, so that the influence of gravity on the "escapement system" in the mechanical watch is minimized and the travel time accuracy is improved.Due to its unique operation mode, it has brought the dynamic artistic beauty of the clock to the extreme, and has always been known as the "king of watches".

The spherical tourbillon wraps the escapement of the watch in two frames that run along different axes. The precise rotating mechanism is like an armillary sphere that measures celestial bodies, making it the most ornamental tourbillon!