its a 3646 type C

we know its a type C from the caseback, number and other engravings

movement, Rolex cal. 618, 17 jewels, no Incabloc (aka Type 1)

typical onion crown

with typical 'Brevet +' engraving

Very nice aged Radium paste gives a reddish colour, a kind of cool 'stealth' feature as the numerals are only visible under good lighting

detail

Panerai engraving

The C series from 1942-43 was supplied to the Italian Navy and also to the German. This specific watch was Italian. Looking at the caseback tells us -

Xa FLOTMAS is short for Decima Flottiglia MAS (Decima Flottiglia Mezzi d'Assalto).
Hope you enjoyed, sorry for the dust - will be very carefully removed in the near future,,,,

HAGWE
Cheers and best from the holyland,
~Asi~
