Weiheng&reg;hot Air Stirling Engine Motor Power Generator Education Toy--kit Model Fd03 Hot Air Stirling Engine Size: 180mm X 90mm X 90mm This stirling adopt great material to produce, double weight of other hot air stirling engine. It is a amazing and fantastic product at this price, it can be a great gift to your families or friends. It also can be used for teaching purpose. Many of our customers comes from school,colleague,etc