Family of Blood's vortex manipulator

The Family of Blood stole a vortex manipulator from a time agent to follow the Tenth Doctor and Martha Jones around the universe, tracking the Doctor's TARDIS until they eventually caught up with him in England in 1913. (TV: Human Nature)

Behind the scenes
Though the Family's vortex manipulator is never seen in the story, Human Nature was the first time on screen the time agents' method of time travel was given an on screen name.