This night light light projects swaying motion of ocean waves and can be used in any dark room. The night light can be powered by a USB cable (included) or 4 AA batteries (not included).The USB cable can be plugged to most USB adapters used for phone charging. The unit can automatically shut down after an hour of use. You can also switch it off using the middle ON/Off button. The Daren waves night light volume can be adjusted using the Volume Up(+) and volume down (-) buttons. It has a minispeaker that can be plugged to your favourite MP3 player using an auxiliary cable.