AEM's Flex Fuel Ethanol Content Sensor Kits measure a vehicle's fuel ethanol content percentage and fuel temperature, which allows users with programmable engine management systems (capable of tuning for flex fuel) the ability to optimize an engine's tuning calibration for fuel ethanol content. While many gas stations label flex fuel as E85 (85% Ethanol and 15% Gasoline), actual ethanol content can be much different. Using AEM's Flex Fuel Ethanol Content Sensor delivers the ability to determine the amount of fuel blend being used at any given time.