The FuelSave™ is a new application of old technology. Basically, it acts like a small battery that helps your car's electrical system perform better. The small device is fitted with a capacitor that once plugged in to your 12v adapter is instantly connected to the car's main electrical system. (capacitors are also commonly used to power the electronic flash in cameras)
The capacitor first charges and then discharges the stored electricity (voltage) when there is a heavy energy demand from the alternator. Heavy energy demand (reduced voltage) is caused by using any electrical accessory in your car including lights, windshield wipers, air conditioning, stereo or any combination of them.
Instead of the alternator and battery having to work overtime, FuelSave™ supplements the required voltage to reduce the load on the electrical system from any accessory that is being used. The reduced electrical demand frees up energy that can be better used to deliver a more constant and steady supply of electricity to the spark plugs and ignition system and in the end helps you to save a lot of fuel.