White noise machine by Marsona Model DS-600A It operates using a power cord or 4 AA batteries (not included). You can choose between 6 different sounds: ocean surf; a distant thunderstorm; a steady, constant background of white noise; babbling brook; gentle lapping water at the lakeshore; or the sounds of crickets and spring peepers on a country evening. It also has a timer function that can be set to turn the unit off after 60 minutes. It also has a volume control. Size: 7" long x 4.5" wide x 2.5" high