AEM's Bosch 4.9LSU 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.