Rotating the flywheel drives the gear cam assembly to rotate. The cam on the assembly will make the tappet rise and fall during the rotation process, and the air valve will be opened and closed through the lever.The instrument is equipped with a light controller. When the gears and cams on the assembly are in different positions, it can indicate that the air enters from the intake pipe and the exhaust gas is discharged from the exhaust pipe.Demonstrate the basic structure and working principle of a four-stroke single-cylinder crude oil engine.The mechanisms of the instrument have been adjusted, and the actions of each component are coordinated and coordinated. Do not disassemble at will to avoid misalignment of actions.The power supply voltage should not exceed 3V, so as not to burn the electric beads.Colour: as shownMaterial: metalPackage Contents:1 * Engine modelOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.