Potion of Fire Breath

From Dungeon Master's Guide, page 187. Found on Magic Item Table B.

Description
''Potion, uncommon. 0.5 lbs.''

After drinking this potion, you can use a bonus action to exhale fire at a target within 30 feet of you. The target must make a DC 13 Dexterity saving throw, taking 4d6 fire damage on a failed save, or half as much damage on a successful one. The effect ends after you exhale the fire three times or when 1 hour has passed. This potion's orange liquid flickers, and smoke fills the top of the container and wafts out whenever it is opened.