J-DEAL&reg; USB Mini Charger Doctor Detector, Amp Volt Digital Reader, Current Voltage Detection Tool, Mobile Power Charging Monitor, Backlight Display (Blue(3.5V-7V)) Connects to any USB socket and show the current and voltage in LED screen with accurate real time Support 0A - 3A / 3V - 6V range with accuracy of 0.01A and 0.01V Extremely Portable and small lightweight size for easy carry Very low resistance for more accurate results Best for Solar panels and power banks to measure the maximum charging current