Smithsonian Motor Works Popular Mechanics for Kids! Learn how a real engine works. Build the ultimate Motor Works engine! A real working battery-powered 4-cylinder model engine with real lights and sounds. Watch the spark plugs fire and the valves open and close. See how the pistons fire with the correct timing and watch the belts and fan turn. Set comes with over 100 parts that screw together easily. Screwdriver included. Requires 2 AA batteries not included.

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