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 take Jack to 27 AD. (TV: Exit Wounds)