This genuine GM (#13507129)continental E85/Flex Fuel ethanol content sensor from Aeroflow Performance measures a vehicle’s fuel ethanol content percentage. This allows users with programmableengine management systems (capable of tuning for flex fuel) the ability to optimize an engine’s tuning calibration for fuel ethanol content. While many petrol stations label flex fuel as E85 (85% Ethanol and 15% Gasoline), actual ethanol content can be much different.Using this E85 Ethanol contentsensor it delivers the abilityto determine the amount of fuel blend being used at any given time. This sensor is a universal fitment with a 3/8" (9.52mm) barbs on either end. It does not include the plug and pins which are sold separately (AF49-1521). This sensor measures 50mm Overall Length, 30mm Overall Width, 80mm Overall Height.