Features: OOTDTY Features: Easy to Operate: Just place it on a cup of hot water, and gently flip the wheel until the wheel can run automatically. Performance: It would observe and know the operational process and more intuitive understanding of the operating principle. A Classical Stirling Engine Model: Made of quality metal, clear body gives you a clear view on how every parts works. Safe for Children: No need to fire an alcohols , safer for children. Fully assembled, no need to install it yourself. Educational Toy: School classroom or laboratory experimental teaching aids, the great gift choice for students, teachers, children. Specifications: Material: Metal Color: As The Picture Shows Package Weight: approx.400g Size: approx.195x95x135mm/7.67x3.74x5.31in (More Size Detail, Please See Photo.) Package Includes: 1Pc Low Temperature 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! _x000D_