MyLaps Hybrid RC4 (2-wire): The Hybrid RC4 (2-wire) transponder is a bridge between tracks who run the latest RC4 and RC5 decoder boxes, along with tracks that still run the older RC2 and RC3 decoder boxes. This transponder is backwards compatible on the old decoders and features telemetry data such as voltage to the transponder and transponder temperature each time the loop is crossed, however it does not support the latest car ID numbers that can be used on RC4 and RC5 decoder boxes.