Maestro's tuning fork
From Tardis Wiki, the free Doctor Who reference
Maestro was in possession of a tuning fork, which possessed seemingly magical properties.
History
Maestro used their tuning fork when The Doctor emitted a sonic sound using his sonic screwdriver to find him. They found him by putting the resonating tuning fork in a nearby puddle, drowning out and cancelling the sonic noise, making the Doctor and Ruby findable. (TV: The Devil's Chord [+]Loading...["The Devil's Chord (TV story)"])
