No battery or other power source needed, just put them under the sun to obsorb energy from the sunshine to make them moving . Micro motor can be driven directly under strong sunlight, running fast. Amazing toy for children and teach them to save our earth using green power. Environmental protection and energy conversion. Nice toy to have fun with your friends and mate. Nice toy & gadget to place in office or home to have fun with your friends and mate. Several colors (black, blue, coffee, yellow) available (shipped randomly).