The Pro128 ECU utilizes twin built-in UEGO drivers for highly accurate wideband input control. Factory recommended warm up strategies are also in place to prevent premature failure of the wideband O2 sensors. We have found that MOST of the failures with aftermarket controllers are a direct result of improper heating strategies, not leaded fuel use. Our racers have reported SEASONS of use without failure! ProEFI utilizes the commonly available and inexpensive LSU 4.2 O2 sensor. This kit contains both a sensor, and a cable to run back to the Pro128 ECU.