Features: 1.Widely used, for children's science projects, physics/mechanical learning, teacher demonstration props in the classroom. 2.Made of high?quality materials, exquisite and beautiful. 3.Hands?on operation, more intuitively grasp its low temperature working principle, deepen your interest in physics. 4.Scientific designs of the overall structure to assure system integrity and stability. 5.Safe and eco?friendly, stable performance, convenient and practical. specification:Condition: 100% Brand New Item Type: Stirling Engine Model Material: Iron Operating Steps: Pour boiling water into the cup, put the Stirling engine model on top of the cup, and preheat for one minute to lower the temperature of the cup water Size: Approx. 9.7 x 12.9cm / 3.8 x 5.1in PackageList:1 x Stirling Engine Model Note1. Please allow slight error due to manual measurement. Thanks for your understanding. 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.