AEM's Bosch 4.2LSU Wideband UEGO O2 replacement sensor kit includes only the sensor (with attached cable and male connector) and is intended to replace an existing mounted wideband sensor used with AEM wideband air/fuel UEGO controllers. These sensors have a laser-etched, calibrated resistor in the sensor's connector body. This resistor is specifically created for the exact sensor that it is attached to. Modifying this will invalidate the sensor's output. The wideband sensor is laboratory-calibrated at the Bosch factory, accurate to 0.1 AFR and never requires free-air calibration when used with an AEM wideband AFR controller. Replacement Sensor for the following AEM Wideband Controllers. AEM Infinity Engine Management Systems 30-4100 - Digital Wideband UEGO Gauge 30-4900 - Wideband Failsafe Gauge 30-2310 - Inline Wideband UEGO Controller 30-2340 - 4-Channel Wideband UEGO Controller 30-2340-N - 4-Channel Wideband UEGO Controller - Nascar 30-5130 - Analog Wideband UEGO Gauge 30-5143 - Analog E85 Wideband UEGO Gauge 30-2320 - X-WiFi Wideband/EGT Controller