Original von 116233
was ist denn das links am gehäuse, wird damit irgendwie der wasserdruck und somit die tiefe berechnet ?
indeed, the black button measures the pressure.
when you push it you'll see that the blue hand will go from 0 till 80 meters (so the harder you press, the closer it will go to 80).

Panerai has a similar watch but the Panerai is a quartz
The JLC uses springs and wheels to measure the depth