DIVEWATCHDOCTOR
Contributor
It's a 2-016 Duro 70: just checked my spare against a chart.
Also realized I must have made a mistake in the list I compiled; I'll do a update soon.
I do not have the exact size of that Oring, but the Old model of the Aladin Sport also had a side compartment to change the 3,6 V AA soldered battery. In the Aladin, which was made by Uwatec in Switzerland (just as the Beauchat), the O ring was a B-015 (9/16"x1/16") and not a B-016.