This model  shows the internal structure and operating principles of an air-cooled two-stroke engine. A cross-section of the carburetor is shown. Hand-powered motion supplied through a crank demonstrates the moving parts of the engine. The crank shaft and piston cycle through the stages of the two-stroke process as the hand crank is rotated. A simulated spark plug uses a small lamp to indicate the firing point. All  construction is  of  aluminum and plastic. mounted on an metal  base with a placard on the base labels all key components. Lamp requires two AA  batteries (not included).