Fuel Shark helps your car’s engine run more efficiently for better gas mileage. The Fuel Shark couldn’t be easier to install. Simply plug it into your car’s cigarette lighter adapter. The blue light will come on to let you know it’s working and you’re saving money. By stabilizing your car’s electrical system, you’ll experience enhanced performance including increased gas mileage. The Fuel Shark is amazingly affordable and it lasts for years.