Here's a quick video describing the differences between two versions of the Leica Q2 Ghost by Hodinkee. One version is considered the "Set" which is limited to 150 units while the other version is the "non-Set" version with a total production of 2,000 units.

You can still order the 2,000 unit version on Amazon while supplies last - https://amzn.to/3OH758o

As for the 1 of 150 version, it's best to check ebay as they do pop up from time to time.

Happy searching!