Features: * Voltage and Ammeter Power Capacity Mobile Power Tester Battery Capacity Tester 1. It is a sturdy and practical USB multifunction tester. 2. Long press the button for 3 seconds to view the current single set of stored data (time, Wh, mAh). 3. Click the button to save packet data (time, Wh, mAh). It is practical. Digital display. 4. Portability: This product is small in size and light in weight, which is very convenient to carry around. 5. Good quality: This product is made of high-quality materials, exquisite workmanship, very good quality and long service life. Specifications: Size: 73*23*13.5 (including USB) Voltage: 4-20V1% Current: 0-3A1% Time: 0-99H Capacity: 0-99999mAh Weight: 20g color:Blue Product Introduction: IN-input terminal is connected to the output port of the charger RTZ-Clear button, the screen display is cleared after pressing for 3-5 seconds OUT- The USB port where the output terminal is connected to the data line Input voltage display window (3-9V) accuracy 1% Charging current display window (0-3A) accuracy 1% Battery capacity display window (0-99999mAh) Working time display window (0-99H) in minutes Working time and empty volume display after power failure, memory function