The Chime of Tezchaptl
From Tatters of the King
An intricately carved silver bell found at Lawrence Bacon's home. According to the Turner Codex the Chime can be used to absorb, and later release the energy of any magical ritual involving performance, be it music, song or recitation.
This artifact was given by the investigators to Alexander Roby while in Carcosa in the hope that he might be able to use it to defeat Montague Edwards in a way that would not cost Roby his life. It is unknown whether this was successful.
Full instructions for its use are in the book.