100-240V refers to the voltage range of an electrical circuit. It is a universal standard for many electrical outlets around the world. This range of voltage allows for a range of power sources to be used in different countries. It is important to note that the voltage range does not indicate the amount of power that can be used, but rather the amount of power that can safely be used. The higher voltage allows for more powerful devices to be used, while the lower voltage requires lower powered devices. Knowing the voltage of your electrical circuit is important in order to ensure safety when using electrical devices.