Baldur's Gate Wiki

This is an undroppable item typically worn in one of the creature's ring slots that grants the always on ability to see invisible creatures by script. Basically, it allows invisible creatures to be attacked by the wearer's assigned AI script (ignoring the invisibility shielding and targeting detection protection provided by invisibility).

This includes creatures hidden by Hide in Shadows/Stealth and creatures under the Sanctuary spell, Invisibility and even most aspects of Improved Invisibility.

Further, the Non-Detection spell or items that provide it, has no effect on this item's ability to see invisible.

The item is equipped by a number of different creatures in the game. It provides no other abilities.