Frei in California sells Stella plastic crystals that use a white or yellow tension ring (crystal has inner groove cut for this ring). Generally these work by installing the original Heuer minute marker ring in place of the tension ring. You need to know the OD of your crystal and order 2 that are the closest OD. One of them will work. Getting the marker ring aligned perfectly is the trick. Best to put a mark on the case before removement the old one so it will align. Also needed is a crystal compressor.
If you haven't done this before, best to get someone who knows how to do it. Good luck!

: Hi folks, hope you're all well.

: I've cracked the crystal (or plastic) on my Carrera 3647
: black-face. Is there anyone reliable in London can fit me a new
: one? Failing that, I'll be in NYC for a week in July (but
: rushed).

: Thanks in advance for your suggestions,

: Paul

: here is the beastie, as captured by its previous owner, David (my
: photos all show my skinny hairy wrists and you don't want to see
: those...)

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