HistorySpeed Force transmitter.
Iris West's watch began to go off as she kissed her "husband" (Earth-1 Barry Allen in disguise), though she brushed it off as a glitch. Later at Jitterbugs, the patrons' watches began to go off just before Killer Frost and Deathstorm burst in.
Jesse was given her father's next gen watch when she went clubbing with Team Flash. Tired of the meta-human awareness app constantly beeping in Barry's presence, she tried to use her hairpin to disable the watch. In doing so, Jesse accidentally stumbled onto Harry's recording.
Team Flash seems to own at least one of these devices, as they gave Nora West-Allen a watch and sent her to activate it next to Spencer Young when the team tried determining if Spencer was a meta-human.
- Meta-human detection: Using the meta-human awareness app, the watch will produce a red alert in the direct presence of a dark matter-empowered meta-human.
- Audio recording: The watch can be used as a recording device.