Am I missing something?

[jantjewgm]

Hello there,
Is recently purchased a crown for my gold filled 2448 carrera. I measured the stem thread and it is 0.9mm (tap 10).
I ordered the following crown from ebay;
https://www.ebay.com/itm/2555666684...73&osub=-1~1&crd=20230605134857&segname=11051

It says the crown is for a tap 10 stem. However, the thread is too thick to fit the whole.
Did I miss something? Do I misunderstand how to measure?
Thanks.