Glycine Combat 6 43mm Watch

I have to say, that argument against a display back is not convincing.   I would ask the designers (not the owners) of the Planet Ocean if they would dive with theirs.  I think they would say "yes".  It is only the fear of messing up their expensive pro dive watches because of proximity to water (an unfounded fear) that most just take out their trusty Seiko 007's during a dive.  They wear the Planet Ocean at the post-dive lobster dinner.

Front and rear crystals use the same technology, glue. My point is that a rear crystal on a REAL dive watch adds a point of failure, a seam sealed by glue. A case-back is threaded and has a gasket. Crowns and pushers are threaded and use gaskets. The science for sealing a dive watch crystal is simple, water pressure pushes the crystal against the case. This also flexes the crystal which makes it an eventual point of failure. Omega doesn't bother with a display back with its 300m Seamaster but does use one on its 600m Planet Ocean and 1200m Seamaster Proprof? A display back on a serious dive watch is done for vanity, not practicality. But then probably 95% (or more) of the high end Swiss dive watches never go diving so that's why they do it. I own an Omega Speedmaster Chronometer. It has a 100m 'water resistance' rating. I don't even wear that watch while I shower.

We can at least agree that high end watch companies have figured out how to have a waterproof display FRONT.  It's not a huge reach to believe that they have figured out how to design a waterproof display BACK...  is there some super-secret technology that differentiates the two?  Educate me.