As the smallest, least expensive, not to mention first fuel cell car to be powered by saltwater, the Salt Water Fuel Cell Car gives kids a chance to learn about new forms of clean energy, while building and powering their very own toy: Just add saltwater and go! The company says assembly time in only about 10 minutes. (Probably 2 hours for me, 3 with swearing.) After activating the fuel cell module with a saltwater mixture, the magnesium metal sheet (3 sheets included) can operate the car for about 5-7 hours continuously. If you want to park the vehicle, simply take out the fuel cell module and rinse with tap water and dry. All the materials used in this kit are environmentally safe and clean, non-toxic substances or disposal concerns. www.owirobot.com Retail is about $16.00