Lens of Truth
The “Lens of Truth” allows the user to see through Illusion as well as things that are not normally visible to the naked eye. It shows which walls, floors, and objects are not real and it allows the user to see things such as, invisible ladders, platforms, enemies, and ghosts. Be warned, as it drains magic power over time.
The Lens of Truth looks very similar to the Sheikah's (Shadow Folk) eye symbol, with the handle as the tear. It is speculated to be part of a set of three objects, including the “Mask of Truth” and the “Stone of Agony”—these were created to give their holder untold power in terms of perception of the truth of their surroundings.