What is this

[Papa]

The personal transponder is an electric device that is powered from the RX. It is used by a AMB timing system. It counts laps and records time through a wire loop that is typically laid under the start line of a race track and sends the data to a trackside computer. A transponder is needed to race at most organized tracks. Most tracks have loners for the drivers that do not have personals. They are stored in a charging rack and are assigned based on car numbers.