The mouse's power source is a lithium-ion battery. To recharge it, you simply set it on a very well-designed base station. Not only does it look elegant, but its shape lets you easily place the mouse on it. Three green LEDs on the top of the mouse keep you informed of the amount of battery power that you still have left. The battery life is amazing. We've been using the mouse for three weeks and still haven't recharged it. The indicator still shows two bars out of three! This is by far the most user-friendly cordless mouse where power is concerned.