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You have found a potion from the Tavernmaster's private collection! Feel free to use it in your role-playing sessions. If you are a player, assign it to ONE of your characters. If you are a Game Master, be sure to remove the label before placing the bottle in your dungeon...

Sonic Water (3 dose)

A gulp of this cool refreshing water greatly improves one's hearing. For the next 10 minutes you can hear any sound that is at least as loud as a whisper through a thick wall or at a distance up to 50'.

However, for the 10 minutes following that you can hear nothing at all!