The Illumination's collar
From Jenny Everywhere Wiki
The Illumination's collar was a thick metal collar worn by the Illumination by choice to keep his blinding power in check, allowing him to interact with normal humans. He could take it off at will to demonstrate his full power, and remained invulnerable even while wearing it, though he ceased to glow. The collar was emblazoned with his sigil as an Abstract. (COMIC: The Jenny Everywhere Chronicles)