Tachyon prototype

The Tachyon Prototype is a device developed by Mercury Labs that can absorb the "Speed Force".

While a technician was monitoring it, a Man in yellow attempted to steal the device but was prevented from doing so by the technician who locked the door to the Prototype's chamber. Believing that the device would serve as an effective lure for the man in yellow, Barry Allen procured it from Dr. Tina McGee and brought it to S.T.A.R. Labs where Cisco Ramon, Caitlin Snow, and Harrison Wells had built a trap for the man in yellow. Despite these precautions, the man in yellow managed to steal the device. Harrison Wells later put it on the chest of his suit.

Harrison acknowledged to Gideon that the device is a stopgap measure, rather than a cure for his problems with his superspeed.