bayareauser2Web search showed reviews that state this is a modified sine wave inverter. I would agree because of the price point. Getting a modified sine wave inverter with a 100Wh battery for $120 is market price, some are even a little cheaper. In addition, they are targeting laptop and other electronics for using the AC adapter, which only need modified sine to work, albeit less efficiently. It would cost more if it had a pure sine wave inverter.