ITEM NAME:Electric Current Volt Doctor Digital Voltage Ammeter Charger Capacity USB Tester Product Description Description: USB Detector Current Voltage Meter Doctor Charger Capacity Plug and Play Power Bank Tester Voltmeter Ammeter Feature: It measures the current and voltage of the power supply device through the USB port. Plug and play, no additional power supply required. The voltage and current will show a circle. Small size, easy to carry. Specification: Input/output voltage: 4-20V Voltage resolution: 0.01V Input/output current: 0-3A Current resolution: 0.01A Accuracy: Â ±1% Material: ABS+PC Size: 59*23*13.5mm/2.32*0.91*0.53" Note: Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! Please allow 1-3mm measuring deviation due to manual measurement. Included: 1 XÂ USB Tester.Included: 1 X USB Tester. Input/output current: 0-3A. Current resolution: 0.01A. Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures.