Cyclic Current and Voltage Display: This USB tester features a color LCD display for clear and easy-to-read data. Its compact size requires no additional equipment, such as a power supply. Plug-and-play, it retains data even after a power outage, preventing loss. Product Advantages: This USB current and voltage tester easily and effectively measures the output voltage of USB ports and the operating current of devices. Complete Configuration: This power meter is equipped with a precision bandgap reference source, providing accurate ranges, high accuracy, stable operation, reliable performance, excellent anti-interference, and high temperature resistance. Easy to Use: Simply plug this compact device into a USB port and read the output on the screen to check the proper operation of the USB cable. Application: This tester can measure the voltage of a USB power supply when not in use, the voltage and current of a USB port when in use, and can also check the compliance of the voltage and output voltage of a USB charger.