VIMVIP USB Car Charger Doctor Voltage Current Detection Tool (3.5V-7.0V, 0-3A) Compact and easy to carry, no additional power supply. Current and voltage loop display, easy to use and practical. USB charger can detect whether the target output voltage and current. Convenient measurement of the output voltage of the usb port and the device operating current. Package Include:1x VIMVIP USB Car Charger Doctor Voltage Current Detection Tool.