Removing bezel

[KJ2020]

That would work if the opening is gen-spec but a lot of these cheaper reps are 30.5mm not 29.5mm (no stairstep indent edge profile). Also need to verify where the date window is, is it DG/ETA or Rolex position?

From the appearance of the gasket, I'd say it's not gen spec

 

[emameme]

Yes, it's a 30.3 mm
I will try to buy on AliExpress a 30.4 and sand it if necessary.
Thanks a lot guys

 

[KJ2020]

Check your date window position before ordering.

Yours is a DG/ETA date window position. Post a link to the crystal you find, we can advise. You need one like the one on the right in my pic above.

 

[KJ2020]

Your measurement is OK, but it's probably a little larger. The gasket has an L shape, it's lower edge has a smaller diameter than its upper. When measuring, care must be taken not to catch any of the lower, smaller diameter L indent.

That you measured greater than 29.5mm is sufficient info to proceed with purchase of a 30.5mm straight edge side profile ETA cyclops position crystal.

 

[emameme]

I have tried to search a specific sapphire for ETA but nothing...
Then I have find this
https://a.aliexpress.com/_dV3tSqv or this one
https://a.aliexpress.com/_dU2Ytcp

 

[KJ2020]

Both of these list two measurements, indicating there is an indented stairstep side profile like the gen has. This is not what you need. First one is way too small, outer diameter is 21.3mm

Second one fit is good 30.4mm outer but you need a flat side edge to reach your gasket opening of 30.3mm. BTW you won't be sanding sapphire, it's the tight fit that keeps it in place.

 

[emameme]

I think this is what I need. https://www.ebay.co.uk/itm/332698924101

I think that I will try with this:
https://a.aliexpress.com/_dTjJldB
Version 30.4mm