Great fun motor, will work with many power sources batteries and solar cells work perfectly Easy to install and disassemble, suitable for many projects at home and in your classroom. Great for robot toy, student lab project, STEM class, motor powered cars, engineering class and more Tips: Mini size, easy to install and save, put them in a sealed bag when not in use to prevent damp rust Shaft length - 8mm. Operating voltage range = 3 - 6v. Nominal operating voltage = 5v.