Air/Fuel Monitors and accessories are designed to help performance enthusiasts calibrate an optimum air/fuel mixture ratio. The monitor will work on carbureted, injected, supercharged or turbocharged engines using unleaded gasoline, alcohol, or nitrous oxide. Air/Fuel Monitor uses an electric signal from an oxygen seneor to illuminate a group of 10 LED lights that correspond with an air/fuel ratio scale. Reading the scale will tell if your fuel calibration is rich, lean or just right. Using the Monitor as a tool, a tuner can adjust for peak performance, economy and/or drivability under any load condition or throttle setting.