1[Working Principle] Stirling engine is a kind of heat engine that operates at different temperature levels by cyclically compressing and expanding air or other gases (working fluids), thereby converting heat energy into mechanical work. 2[Aluminum Alloy Material] Made of high quality aluminum alloy material, whichi is durable, wear resistant, not easy to rust, and long service life. 3[Exquisite Workman] Stirling engine model is exquisite in workman and beautiful in appearance, making it the ideal choice for home decoration. 4[Physics Mechanical Learning] Stirling engine model is a great gift for children's science projects, it helps children learn physics and mechanics. 5[Widely Application] Widely used in classroom teaching props, birth gifts for friends, family, parents, and children. Item Type: Engine Model Material: Aluminum alloy Model Product Size: Approx. 18 x 9 x 8 cm / 7.1 x 3.5 x 3.1 in Application: For children's science projects, physics, mechanical learning, classroom presentations Weight: Approx. 527g / 18.6oz 1 x Engine Model 1 x Ethanol Lamp 1 x Add Ethanol Tool 3 x Hex Wrench 1 x Sealing Ring 1 x Roller Pin 1 x Silicone Tube 1 x Chinese And English Manual Accessory ethanol bottle (without liquid)