Dorium Maldovar's gravity wave manipulator
From Tardis Wiki, the free Doctor Who reference
The Wavemasters of Arkethon gave Dorium Maldovar a gravity wave manipulator which looked like a silver pendant. It was capable of manipulating localised gravity, allowing Dorium to create self-sustaining force fields, move objects and bend light.
Dorium used the manipulator to create a force field around the TARDIS, preventing the Eleventh Doctor from leaving the Maldovarium until he repaid his debt. He used it to save the Doctor and Plume from falling in the Beacon, after which Plume stealthily stole it from him. She later gave it to the Doctor, who used it to deflect the Lux into Geryon's Eye. (AUDIO: The Light Keepers)
