USB Current & Voltage Meter, Black; Amps & Power Meter for USB charger, smartphone and USB devices Great for measuring: charge current/voltage of phones & tablets; output capabilities of USB ports, power supply and chargers; power consumption/demand of USB devices. Large easy-to-ready LED displays both current (A, Amps) and voltage (V, Volt) at the same time, with 1% accuracy. It supports input 3-9V and max current of 3A, with 2 output ports to charge 2 devices at the same time. Compact one piece design, easy to carry around and straightforward to use. Warning: input voltage exceeding 9V will DAMAGE device.