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 AFR controller 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 gauge designs are 52mm to fit standard gauge pods and include everything you need to install them. Both designs include outputs to transmit AFR data to a logging device or engine management system. If you do not need a 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 wideband controllers. Trust AEM, the pioneers of the wideband gauge.