Specifications: This is an external combustion engine in which the fuel is burned continuously, and the piston is moved by the expansion of air (or helium or hydrogen) as a medium, and the expansion gas is cooled in the cold chamber, and the cycle is repeated. Only a small alcohol lamp, you can make it fast rotation and strong power. As the external combustion engine to avoid the traditional internal combustion engine of the explosion to do work, in order to achieve a high efficiency, low noise, low pollution and low operating costs. Aerodynamics are rich in knowledge of physics, single cylinder combustion engine. Engine principle is intuitive, educational toys, teaching experimental equipment can effectively cultivate children& 39;s interest in learning can also be used for classroom teaching, more intuitive and easy to understand. Type: Stirling Engine Model Material: Metal, Glass Size: 16.5cm x 8.7cm x 9.5cm/6.50" x 3.43" x 3.74" (Approx.) Notes: Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Stirling Engine Model 1 x Alcohol Lamp (Alcohol Not Included)