Experience the most promising energy technology of the 21st century and assemble your own hydrogen car. The fuel cell car kit uses a reversible PEM (proton exchange membrane) fuel cell. This works both ways: As an electrolyte (to produce hydrogen from water) and as a power source (to produce electricity from hydrogen). Once hydrogen has been produced, the fuel cell can convert it into electrical energy to power your car's engine. When the car is running on hydrogen, two bright green LED lights mounted on the car's engine flash. The car will autonomously drive around any obstacles that are in its path. It will turn around or back up until the path forward is clear.