Magnetic Fuel Saver Device for Cars, Vehicle Fuel Efficiency Enhancer for Gasoline and Diesel EnginesSupport for Everyday Driving Costs Fuel costs can add up quickly during daily commutes, errands, or longer drives. This plug in fuel saver device is designed to help support more efficient vehicle operation by interacting with the cars electrical system. It may assist drivers looking to manage fuel usage during regular driving without changing driving habits. Actual results may vary depending on vehicle condition, driving style, and road conditions.