Wondrous item, rare
The rattle has 3 charges and regains all of them at dawn. As an action you can sound it and expend 1 charge. Every creature within 300 feet that is asleep, and that has within the last year done a thing for which it fears being taken up by an officer of a city, wakes at once and knows that it woke to a rattle. Every other sleeper within that distance is not woken, hears nothing, and rests on undisturbed.
It does not wake a creature held asleep by a spell or other magic. It carries through shutters, doors, walls, water, and fog, and it does not carry to anybody it is not for.
You learn nothing of what any of them did. You learn who woke, and in a boarding-house that is a great deal.
The rattle has never failed to wake the person holding it.
Source: Provenance — The Quist Sale