This Stirling engine model can clearly explain the principle of aerodynamics. Features: How It Works A Stirling engine is a heat engine that operates by cyclic compression and expansion of air or other gas (the working fluid) at different temperatures, such that there is a net conversion of heat energy to mechanical work. Intuitive Explanation Teaching will be more intuitive and more interesting. Easy to Understand Student can understand it quicker and better. Easy to Install The assembly process is quick and easily. Specifications: Model: LL-002 Material: Galvanized Iron Sheet & Speed: Up to 200rpm Engine Size: 16.2 * 8.8 * 8.3cm / 6.4 * 3.5 * 3.3" Engine Weight: 308g / 10.8oz Package Size: 17.5 * 9.2 * 11cm / 6.9 * 3.6 * 4.3" Package Weight: 464g / 16.4oz Package List: 1 * Stirling Engine Self-assembly Kit 1 * Alcohol Lamp (Without liquid) 2 * Spare Tube 1 * User Manual(English/Chinese) Note: 1. should not be exposed to water after being heated, or otherwise it will split. 2. If the alcohol is spill, please use wet cloth to put out the fire. 3. Children under 12-year-old should be accompanied by adult when using this product.