1Working Principle: Stirling engine, which converts thermal energy into mechanical work by circulating compressed and expanded air or other gases (working fluids) at different temperature levels. 2Aluminum Alloy Structure: The Stirling engine model is made of highquality aluminum alloy materials and fine craftsman to avoid rust and prolong the service life. 3Physics Model: A great educational toy, classroom or laboratory experiment teaching aid, which is conducive to cultivating children's interest in physics. It is a great gift for anyone interested in science. 4Mechanical Toy: It is a well designed and manufactured mechanical toy, which is very suitable for visually showing the basic principles of external combustion engines. 5Innovative Gift: A great model car with Stirling engine, which can move forward, backward, and simply turn. It is very suitable for friends, family, children, etc. Item Type: Stirling Engine Model Car Material: Aluminum Alloy Weight: Approx. 991g / 35oz Product Size: Approx. 25.8x10.3x12cm / 10.2x4.1x4.7in Features: It can move forward, backward, and turn easily 1 x Stirling Engine Car2 x Gasket1. Please allow 0& 8209;1 inch 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.