Description: Four-stroke internal combustion engine model, brand new and high quanlity Great educational toy, classroom or laboratory experimental teaching aids, cultivate children'sinterest in physics, more intuitive and easy to understand Product parameter： Size(L x W x H): 30x 17 x 2.5 mm/ 11.8x 6.6 x 0.9 inch Color: As picture show Package Includes: 1 x Combustion Engine Model matters needing attention 1. The various mechanisms of the instrument have been adjusted before leaving the factory, and the actions of all components are unified and coordinated. Do not disassemble at will to avoid movement dislocation. 2. A small amount of lubricating oil can be added to the rotating and sliding parts of the instrument to keep the movement flexible. After use, wrap it in a plastic bag and store it. 3. The power supply voltage should not exceed 3V, so as not to burn the bulb. After the experiment, take out the battery. Note: Due to the manual measurement, please allow 1-2mm differences in size. Due to the light and screen difference, the item's color may be slightly different from the pictures. Please understand.