Lantern of Greyhawk

This hooded lantern was found for the first time in the abandoned castle of Zazyg Yragerne, the Mad Mage. When you hold this magic item, you can use a Magic Action to activate a 30-foot Cone's that originates from the lantern. You gain Truesight within the Cone' space. The Cone lasts for 1 minute or earlier if you dismiss it as a Bonus Action. Once you use this property, you can't use it again until you finish a Long Rest.