The Starpower Self-assembly Stirling Engine Motor Model Education Toy is a DIY all-metal structure that can be repeatedly disassembled and assembled. This model is designed to exercise the hands-on ability and features a one-piece design for the hot cylinder, hot cylinder liner, power cylinder liner, and power cylinder which makes assembly easy. The cylinder liner is a sheet-shaped heat dissipation structure and both ends of the bracket are equipped with a large alloy flywheel and a small flywheel. High-precision imported bearings are used between the flywheel shaft and the bracket. This educational toy comes with an alcohol lamp and instructions on how to start it up. Please note that during heating, do not touch the cylinder and heating portion. Also, avoid other liquid substances coming into contact with cylinders in case of cylinder rustiness. If the model is not running well, please check if there is enough alcohol in the alcohol lamp or if the small and big wheel jackscrews are loose or not. We offer a 30-day free return policy with no reason. Shipping time to the United States is 2-6 business days and we prefer PayPal for payment.