Description: It can measure the voltage when the USB power supply device is empty and load, and the voltage and current when the USB terminal device is working. The use of the original imported single-chip sampling and display voltage, and in the software for a large number of data processing, so that the display is accurate and stable. All-spot technology, exquisite workmanship, while the ultra-small size. Current, voltage cycle display, easy to use and practical. Small and easy to carry, no need to connect another power supply. Specification: Measurement accuracy: 1% Refresh rate: about 200ms Display mode: alternating current and voltage display Voltage measurement range: 3.5V-7V Current measurement range: 0A-3A Working current: 20mA Storage temperature: -10 °C to +65 °C Meter voltage drop: 200mV Package Includes: 1 Piece USB Charger Doctor