Feature: 1. ★ Easy to Operate: Just place it on a cup of hot water, and gently flip the wheel until the wheel can run automatically. 2. ★ Superior Performance: By operating the engine, children would observe and know the operational process and more intuitive understanding of the operating principle of Stirling engine, deepening interest in physics. 3. ★ A Classic Stirling Engine Model: Made of premium metal, and the high intensity PC material is heat-resistant and harmless. Transparent body gives you a clear view on how every parts work. 4. ★ Safe for Children: No need to fire an alcohol lamp, safer for children. Fully assembled, no need to install it yourself. 5. ★ Great Educational : classroom or laboratory experimental teaching aids, the best choice gift for students, teachers, children, friends and colleagues. Specification: Features: ★ Easy to Operate: Just place it on a cup of hot water, and gently flip the wheel until the wheel can run automatically. ★ Superior Performance: By operating the engine, children would observe and know the operational process and more intuitive understanding of the operating principle of Stirling engine, deepening interest in physics. ★ A Classic Stirling Engine Model: Made of premium metal, and the high intensity PC material is heat-resistant and harmless. Transparent body gives you a clear view on how every parts work. ★ Safe for Children: No need to fire an alcohol lamp, safer for children. Fully assembled, no need to install it yourself. ★ Great Educational : classroom or laboratory experimental teaching aids, the best choice gift for students, teachers, children, friends and colleagues. Specification: Model: D2 Material: Metal,PC Size: 9.9 x 10.7cm(DxH) Weight: 193g/6.8oz Package Size: 19 x 10.8 x 13/7.5 x 4.2 x 5.1in Package Weight: 307g/10.8oz Specification: 1 x Stirling Engine Model Package List: 1 x Stirling Engine Model