"World-Famous" Wideband O2 air/fuel ratio UEGO gauge features a digital LED display and sweeping LED 'needle' that changes colors as AFR changes from rich to lean. A 52mm (2-1/16"") gauge housing ensures that it will fit in most gauge pods and can be remotely mounted virtually anywhere. All AEM® digital gauges feature a 0-5v analog output for use with data loggers and almost any engine management system. Each gauge comes with black and silver bezels and black and white faceplates for multiple color combinations and a custom look (a black Lambda faceplate and black and white Air/Fuel Ratio faceplates).