Features: Science Educational Toy: As the flywheel rotates at high speed, feel the magical process of energy conversion, observe that power generation voltage at any time, and can light up multiple light bulbs at the same time. A Classical Stirling Engine Model: Made of quality alloy materials, clear body detail gives you a clear view on how every parts works. Working Principle: It outputs power through a cycle of cooling, compression, heat absorption, and expansion of the air in the cylinder. High Performance: It would observe and know the operational process and more intuitive understanding of the operating principle. Educational Toy: School classroom or laboratory experimental teaching aids, the great gift choice for students, teachers, children. Specifications: Material: Alloy Color: Golden/Colorful Package Weight: approx.510g Size: approx.195x105x135mm/7.67x4.13x5.31in (More Size Detail, Please See Photo.) Package Includes: 1Pc Stirling Engine Model note: Please allow 1-3mm error due to manual measurement. Please make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thanks!