Very thin (around two inches wide), almost totally flat, circles just under two feet in diameter. Composed of a bright, bright silver-y metal that is clearly not silver, nor steel, nor any metal common to this world. Unnaturally smooth and precise, with an appearance of being machine-tooled. Lined on one side with a series of metal buttons and tiny crystal demi-spheres. There are words engraved into them in an unknown language. They radiate strong psychic conjuration magic and seem to be representative of Mi-go technology, like Confabulation Plates.
First Reference: Chapter 183
Other Notable References: Chapter 185