Features: brand new and high quality [Material] Metal + Wire + Quartz Glass + Plastic. Quartz glass and gears are made of plastic. The base, bracket, flywheel, heating cylinder, and connecting rod are all made of metal, which is sturdy and durable, and is not easily damaged during the assembly process. [Size] 12.5x9cm/4.92x3.54inch. By operating the engine, children will observe and understand the operation process of the Stirling engine, understand the working principle of the Stirling engine more intuitively, and deepen their interest in physics. [Simple operation] The product is easy to install and has been debugged. When installing the product power cylinder, you need to gently rotate the belt, pay attention to use 95% alcohol (self-provided), do not add water, kerosene, gasoline, lighter oil, liquor, etc. [Innovative design] Creatively combine the Stirling engine model with the toy car, using the Stirling engine model as the power, driving a simple toy car to walk, with diverse playing methods and endless fun. [Wide range of application] This model kit has a wide range of applications, such as children's science projects, physics/mechanical learning, teachers, classroom demonstration props, friends, family members, parents, children's birthday gifts, etc. Specifications: Material: Metal Weight: 420g Size: 12.5x9cm/4.92x3.54inch Package Includes: 1x Stirling Engine Car note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.