These rings are created and sold by username xxmateleaxx at Yahoo! Japan, though of late, a few have begun showing up on E-Bay. They are constructed from a pre-made metal ring with the signet face and reflective cover attached later; xxmateleaxx states that he is not the manufacturer of the metal ring but obtains them specifically for use in these signets. Similar rings for other anime, noteably Naruto, are also available from xxmateleaxx using the same basic design. Acquiring one of these can be a bit of an undertaking. Unless you find one on E-bay, getting one out of Japan is problematic unless you have someone to ship it to you, or use an auction house like Rinkya and their fees increase the overall cost.