AEM's Wideband UEGO (Universal Exhaust Gas Oxygen, pronounced “You-Way-Go”) Controllers are powerful, cost-effective tuning tools that allow users to accurately monitor the Air/Fuel Ratio (AFR) of an engine. AEM was the first company to release a wideband air/fuel ratio gauge with its Classic Digital Wideband and delivers the fastest-responding wideband air/fuel controller with its patented X-Series wideband technology, which allows you to see AFR changes other controllers may miss. Both wideband air/fuel ratio gauges are 52mm to fit standard gauge pods and include everything you need to install them. Both wideband gauge designs include outputs to transmit AFR data to a logging device or engine management system. If you do not need an air/fuel ratio gauge, the X-Series Inline Controller is ideal for users who only need AFR data for logging, feedback control, and/or transmitting to a dash display. AEM also offers wideband sensors, bungs, and no-weld installation mounts to satisfy the installation needs of everyone from the weekend racer to the professional. When you want the best tune, you need the best air/fuel controllers. Trust AEM, the pioneers of the wideband gauge.