GoolRC Cute Solar Mini Tortoise Crystal Solar Powered Tortoise Insect Solar Toys for Kids When exposed to sunlight, the solar tortoise can start its mini-engine by shaking itself(need to be on the plane surface) Powered by solar energy, no battery required. It must be placed under the strong sunlight, till it works. The solar tortoise is a good teaching mold for solar concept of your children. Made of single crystal silicon manufacture technology, it is more energy-saving and eco-friendly.