1、WORKING PRINCIPLE Stirling engine operates at different temperature levels by cyclically compressing and expanding air or other gases (working fluids), converting thermal energy into mechanical energy. 2、STIMULATE CURIOSITY This engine model is very suitable to demonstrate the basic principles of external combustion engines and cultivate children's interest and curiosity in physics. 3、MULTI PURPOSE Stirling engine model is a well designed and manufactured mechanical toy, and it is also an excellent educational toy, classroom or laboratory experiment tool. 4、DURABLE AND PRACTICAL Using high quality aluminum alloy material, the structure is stable, durable and corrosion resistant, avoiding rust, and prolonging the service life. 5、WIDE APPLICATIONS Designed for children's science projects, physics and mechanical learning, teacher classroom presentations, also a good birthday gift for friends, family, parents, colleagues, children, etc. Item Type: Stirling Engine Model Material: Aluminum Alloy Weight: Approx. 510g / 18oz Stirling Engine Model Size: Approx. 18x9x8cm / 7.1x3.5x3.1in Scope of Application: Children's science projects, physics and mechanical learning, classroom presentations, etc. 1 x Engine Model 1 x Ethanol Bottle (Without Liquid) 1 x Wick 1 x Accessory 3 x Hex Wrench 1 x Cylinder 1 x Piston 1 x Sealing Ring 1 x Needle Roller 1 x Silicone Tube 1 x Chinese and English Manual