This is the "LPA-CIVT150BK" DC-AC inverter from Logitec. It converts a car's cigarette lighter socket (DC12V) to household power (AC100V) and USB power (DC5V/1A). The rated output is 150W (maximum instantaneous output 300W). It's useful for charging laptops and tablet PCs in the car, and also as an auxiliary power supply during power outages and disasters.