When initially found or purchased, this well-made leather belt pouch contains a plain silver ring. It has a top flap that closes with a silver button. Once a creature wears the ring, the pouch's magic takes hold. Any time someone other than the ring wearer opens, grabs, or moves the pouch, it emits a piercing shriek audible for 200 feet. The shrieking stops in 1 second if the offending creature drops the bag or otherwise leaves it alone. It causes no damage, but it definitely attracts attention.
Originally designed as a wealthy person's bauble to foil cutpurses, various thieves' guilds use these as puzzles for recruits to work through. Shrieking Pouches see much more use as practical jokes lately, usually involving the owner leaving it in a bar for someone to find. The Sacred Squid has had to implement a zero tolerance policy to eject and refuse to serve anyone with a Shrieking Pouch, as the noise ruins the dining experience for everyone in the entire building.
Bert DeSilva carries one on his person, a parting gift from the Lakeside Six. He pretends to know all about it, but he continuously wonders what makes that noise when he leaves it lying around and someone else moves it back to his desk.