Horn of Blasting is a rare wondrous items in D&D 5e. It does not require attunement.
Wondrous item, rare
You can use an action to speak the horn's command word and then blow the horn, which emits a thunderous blast in a 30-foot cone that is audible 600 feet away. Each creature in the cone must make a DC 15 Constitution saving throw. On a failed save, a creature takes 5d6 thunder damage and is deafened for 1 minute. On a successful save, a creature takes half as much damage and isn't deafened. Creatures and objects made of glass or crystal have disadvantage on the saving throw and take 10d6 thunder damage instead of 5d6.
Each use of the horn's magic has a 20 percent chance of causing the horn to explode. The explosion deals 10d6 fire damage to the blower and destroys the horn.
Frequently Asked Questions
You can use an action to speak the horn's command word and then blow the horn, which emits a thunderous blast in a 30-foot cone that is audible 600 feet away.
The Horn of Blasting is a Rare magic item in D&D 5th Edition.
The Horn of Blasting is a Wondrous Items — Wondrous item, rare.
No, the Horn of Blasting does not require attunement and can be used immediately when held or worn.