... just think of Blancpain's current Fifty Fathoms. However, there the sapphire surface is rounded. To be honest, I think it is a bad idea to have such sharp-edged outlines of the sapphire bezel, as we see on the Ebel. Sapphire is brittle, and damages after rough contacts with hard surfaces (walls, for instance) seem inevitable. Good diving watches normally make sure that the metal bezel ring is higher than the sapphire crystal, thus protecting it from getting damaged on the edges.
Regards,
Marcus