This is my version of the Millennium Ring from yu-gi-oh, it's roughly to scale but is made to look good in person and be easier to make.
I included a few different ways to print the pieces some are easier than others depending on your printer.
The led just uses a button cell coin holder, a slide switch, an led, and a resistor all easy things to get ahold of.
Edit: I added the STL for the top ring because I was made aware it was missing.
The author marked this model as their own original creation.