Easy to Use: Simply place it in a cup of hot water and gently twist the wheels until they spin automatically. Excellent Performance: By powering the engine, students will observe and understand the operating process of the Stirling engine, grasp its working principle more intuitively, and deepen their interest in physics. Classic Stirling Engine Model: Made of high-quality metal, high-strength PC material is heat-resistant. The transparent body allows you to clearly see the working principle of each component. Safety: Fully assembled, no self-installation required. Fantastic Educational Toys: Classroom or laboratory experiment teaching aids, the best gift choice for students, teachers, friends, and colleagues. Specifications: Material: Metal, PC Size: 98 * 115 mm Color: As shown in the picture Package includes: 1 * engine model