Marble Machine a Buildable Battery Powered Marble Machine Also Known As the Perpetual Motion Marble Kit BATTERY POWERED: The Marble Machine is powered by battery. Can also be cranked manually. DIY KIT: A Do It Yourself kit that you can assemble on your own. MADE OF QUALITY MATERIAL AND PERFECT SIZE FOR YOUR DESK: Made of Russian birch wood and measures approximately 4" x 4" x 3". ITEMS NEEDED FOR ASSEMBLY: Philips #1 screwdriver and glue required for assembly. (These items are NOT INCLUDED!)