This USB voltage meter is a helpful tool to determine the conditions of USB devices. A simple meter that you can use to verify that a USB cable's connector will be compatible with your device, the meter will indicate if the voltage and current are within the range that your electronic device is designed for. The workable voltage range is from 3.5-7V, with an accuracy of +/- 0.1V. Measures current from 0-3.0A, with an accuracy of +/- 2%. Lightweight and easily portable, it can slip into your laptop case or handbag to take on-the-go.