1、Heat Engine: Stirling engine operates by cyclic compression and expansion of air or other gas, the working fluid, at different temperature levels such that there is a net conversion of heat energy to mechanical work. 2、Elaborately Crafted: Stirling engine is a meticulously designed and made mechanical toy, very suitable for demonstrating the basic principles of external combustion engines. 3、Experimental Model: Great educational toys, classroom or laboratory experiment teaching aids, used to cultivate children's interest in physics. 4、Premium Quality: The Stirling engine model is manufactured with high quality materials and fine craftsmanship to avoid rust and prolong its service life. 5、Perfect Gift: This good looking low temperature stirling engine could be a great gift for your friends or families or yourself. Item Type: Stirling Engine Model Material: Aluminium Alloy Color: As shown in the picture Product Size: Approx. 9x13cm / 3.5x5.1in Weight: Approx. 271g / 9.6oz Application: Used for children's science projects, physics/mechanical learning, classroom presentations, etc. 1 x Stirling Engine Model 1 x Chinese and English Instruction Manual