DROK USB Port Digital LED 3in1 Display USB output Voltage: DC 5 0-5 1V; USB output current: 0-2 1A, built-in fuse Voltage measuring range: DC 8-40v, DC12V/24V; temperature measuring range: -10 ~ 80 C Function 1 : car battery Voltage monitoring, 12V cars/SUV, 24V trucks/buses Function 2 : universal USB charger, Cell phones, digital cameras, tablet PC, for Apple/Android Function 3 : in-car temperature measurement, -10 ~ 80 C