An Ur-box was a complex device of Time Lord design. It recorded events of a specific point in the timeline. It projected that data and information into the Time Vortex, sending false information to time scanners of time-active factions. This allowed the users of the Ur-box to operate without being detected and so change a point in the timeline. Xenaria made use of an Ur-box during the events surrounding the breaching of the time loop surrounding Planet 5. (PROSE: The Taking of Planet 5)