The Millennium Ring is one of seven Millennium Items forged in the sands of ancient Egypt long ago, each with their own unique powers. The power of the Ring is Subversion: it has the ability to detect the presence of other Millennium Items, and steal their powers. Please be aware that the designer is not responsible for possession of the user by ancient, unimaginably evil spirits from the Shadow Realm.
I made the Millennium Ring for a cosplay me and will be doing in May: I'll be Yami Marik, and she'll be Yami Bakura!
This definitely has the most spot-on dimensions/proportions of all the rings I've seen, and it's just overall awesome.