In short,
link it's a very complicated beast of a movement, and its centerpiece complication is the so-called Chrono Chime, which is activated via a button on the case (look for the one marked by a single musical note). When activated, there are three audible
link phases that chime the minutes (a low tone), the seconds in 10-unit increments (a paired tone), and finally the single-digit resolution
link of the seconds (with a high tone).