AEM's legendary Digital Wideband O2 AFR UEGO Gauge is a wideband UEGO air/fuel ratio controller (AFR) and gauge in one. It unites accuracy, speed and control with an easy to read, digital LED display and sweeping LED "needle" that changes colors as AFR changes from rich to lean.
The AEM UEGO (universal exhaust gas oxygen, pronounce "you-way-go") are powerful, cost-effective tuning tools. A wideband gauge is a requirement for anyone looking to tune their car, and a great idea if you just want to monitor your air/fuel ratio. The UEGO is also unique in that it integrates the wideband controller into the gauge body, so an external control unit is not necessary. The included Bosch sensor is also pre-calibrated out of the box, and the unique connector implements a laser-etched, calibrated resistor, which means the sensor never requires calibration of any kind, unlike many competitors' gauges.
The beauty of the UEGO is that it uses a universal lambda sensor (the Bosch 4.9 LSU on newer models, and 4.2 LSU on earlier). This means it can be used for gasoline, ethanol, propane, practically any fuel. It can easily be switched to display in gasoline AFR (default), lambda, or emulate narrowband oxygen sensors and more. It includes four gauge faces: gasoline AFR and lambda, in black and white, and also includes both glossy black and silver bezels.