this is the famous Ethos Fuel Reducer - This is an "ester" based, non-petroleum, fuel reformulator. when mixed with combustible fuel it simply allows the carbons to be released more efficiently, thereby providing for a "cleaner" burn utilizing more fuel and less carbon leftovers. This REALLY WORKS! I've been using in my vehicles for over two years and have seen a tremendous difference in power, mileage, emissions, and maintenance. Great for personal, industrial, commercial, and governmental use. We've had about 5% of cars report no or less mileage from Ethos. This is due to the car's computer readjusting the mixture to make up for the leaner flow. Most people disconnect the battery for a few hours to reset the emissions sensor. Then they've reported much improvement.