A wideband UEGO sensor controller accurately monitors Air/Fuel ratios (AFR) during the tuning process to prevent a lean fuel mixture, which could lead to engine damage. AEM has combined its single-channel wideband UEGO controller and gauge display into one unit, uniting unsurpassed AFR accuracy and control with an easy-to-read interface. AEM?s Gauge-Type Wideband UEGO Controller features a digital LED display and sweeping LED ?needle? that changes colors as AFR changes from rich to lean. The unit?s 52mm (2-1/16?) gauge housing fits in most gauge pods and can be remotely mounted virtually anywhere.