Hi Mendota,
The packaging says:
"HwS 306
Empire Etanche
hochgewolbt"
But please note that it is a little to shallow in my opinion. There is a gap bewtween the inner edge of the bezel insert and the crystal as the crystal sits a little low. Hard to describe in text and my photo skills are not up to showing it, but a slightly taller crystal would be better - probably only 1mm taller would do it.
FYI 306 refers to the diameter i.e. 30.6mm across. They are cheap - £1.65 each from Cousins - so I got a 30.4mm at the same time to see which would fit best, the 30.6mm is a tight fit, the 30.4mm is too small really.
Hope this helps.