Weiheng&reg;mini Hot Air Stirling Engine Motor Model Educational Toy Ha001 Mini Hot Air Stirling Engine Size: 100X45X50MM 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