The Demon Hunters
Eye of Accuracy
A piece of bone that increases your attack power temporarily
Carved from the bones of a true marksman, the device temporarily confers the skill of that bone’s owner to the weapon it touches.
Utility Power – Consumable (Minor Action)
Effect: When touched to a thrown weapon or piece of ammunition, the eye of accuracy confers a +4 enhancement bonus to attack rolls and damage rolls for the next ranged attack made with the item.
(from the D&D Compendium)
This item was found inside the empty eye socket of a basilisk statue in the Temple of Rai Sen Zula.