Feature: 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. Specification: 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. . Package List: 1 x Stirling Engine Model1 x Chinese and English Instruction Manual Note: 1. Please allow 1‑2in error due to manual measurement. Thanks for your understanding.2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.