Eye patch
Eye Patch1
Device Type Transformation/Camouflage
Function: Transforms Mikoto into her Heavenly Maiden form and also hides the fact that she has two differently-colored eyes.

The Eye Patch, when removed, is what causes Mikoto Kujo to transform into Heavenly Maiden. The process on how this occurs is unknown, though the patch also serves the dual-purpose of hiding her 'golden eye' from others.