This is an emergency light that will operate for 30 days or more off two standard D size batteries. Or with rechargable batteries you can charge the batteries with the built-in solar panel during the day and the high efficency LED (light emitting diode) will provide enough light to function as a room "night-light." The small panel provides 3.4 volts DC at 75 mA. The panel measures 2.6' x 3.75".