Huge congrats, mon ami. The Depthomatic is the first mechanical watch with a Depth Gauge, from 1964. The second watch to offer a depth gauge is more famous, the Favre Leuba Bathy 50, from 1966.
I have only managed to own two and the rest are borrowed photos from the internet. There are two kinds of dials design, one with 12,3,6,9 and another full numerals telephone dial (black and silver versions)