John Hart's vortex manipulator

Captain John Hart owned a vortex manipulator. John referred to it as a "wrist strap".

The vortex manipulator sent and received hologram messages. (TV: Kiss Kiss, Bang Bang, Fragments) It muted sound systems (TV: Kiss Kiss, Bang Bang, Exit Wounds) and communicated with (TV: Exit Wounds) and blocked Torchwood's communication systems. John used it to travel through the Cardiff Rift. (TV: Kiss Kiss, Bang Bang)

John used his manipulator to to reunite with Jack and then take him to 27 AD. Gray used it to take control of the Weevils in Cardiff. (TV: Exit Wounds)