PortaPow Premium USB + DC Power Monitor / Multimeter / DC Ammeter Shows the voltage, current, and total energy (mAh / mWh) in real time from any USB socket or DC power source upto 50V. Includes detachable cables to connect to a USB socket, cable screw-clamps to connect a pair of DC cables, and voltage tester cables. Powered by a built in rechargeable battery and can be charged/powered from any USB socket. Does not use any power at all from the device being measured for the most accurate results. Backlit LED screen for use at night. A NEWER VERSION OF THIS ITEM IS NOW AVAILABLE - SEARCH FOR B00LZ07BG0