AEM's wideband UEGO air/fuel ratio sensor kit includes a Bosch 4.9 LSU Wideband UEGO sensor, connector plug, pins and plugs, and mild steel O2 bung. This kit is designed to be an installation kit for a sensor used with AEM wideband air/fuel UEGO PN 30-4110 only. 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.