USED Westhold/Raceceiver Racing Hardwire Transponder - includes the transponder and wiring harness. This unit installs directly to your 12V 

Product details: Eliminates charging hassle. Hardwired directly to vehicle. Hooks to 12VDC battery. Each transponder has a unique serial number that identifies exactly which competitor is crossing the start/finish line, or any other timing point on a course. Unlike standard RFIDs, Westhold's transponders have an ultra high data rate (1mbit/sec) at HF (3-30MHz) frequencies. Because the high data rate generates many data points, the system is able to more accurately determine when a transponder crosses the center line of the start/finish.

NOTE:  This transponder is compatible ONLY with WESTHOLD TIMING SYSTEMS.  There are 2 companies that control most of the timing systems in circle track racing, WESTHOLD and MYLAPS.  Please make certain BEFORE you purchase that your track(s) use the WESTHOLD transponders.  Please feel free to ask questions!