Features: Contains 9 sets of power outage saving functions. Temporarily store current capacity and energy when power is off. Reopen the opportunity to accumulate the current capacity and energy used. Manual removal if no accumulation is required. Voltage current and capacity display on the same LCD screen, no need for cumbersome operations, only need to connect to the USB interface, you can monitor the phones charging status in real time. Intelligently memory charging capacity, can save the mAH input from 9 sets of charging devices after power off. Easy to view and check whether the charging devices capacitance is true. U disk current detection, the working current of the u disk is between 50-100mA, when is exceeds 100mA, the u disk may be faulty. USB interface voltage detection, the external voltage of the USB interface on the computer is 5V5%, the output current is relatively constant, generally 500mA, and the notebook computer only has 100mA. Directions for use: 1: Click the button to view 1-9 sets of charging data. 2: Long press the button for 3 seconds to remove a set of charging data. 3: Double-click the button to rotate the screen to view. 4. Long press the button and insert the USB interface to enter the voltage calibration: For example: (1) If display (5.526V) Then double click button quickly (2) If display(5.528V), then you can click the button to increase the display voltage. (3) Double click button quickly, if display(5.528V),then you can click the button to decrease the display voltage. (4) Then double click button quickly again, if display(5.526V),then click the button one more times, the screen will display Current Calibration! The system automatically performs current calibration and will automatically return to the function home page after calibration is completed. Specifications: Material: ABS Color: White, Black Current: 0-5A Voltage: 4-30V Timing: 0-99 hours Power: 0-150W Capacity: 0-999999mAh Inner temperature: 0-80 Divide into groups: 0-9 group Charging resistance: 0-999.9 Positive voltage: 0-10V Negative voltage: 0-10V Item size: 56.6*24.7*11.2mm Item weight: 13.9g Package size: 14.7*9.4*1.2cm/5.78*3.70*0.47in Package weight: 17.3g Note: If the output voltage exceeds the allowable charging voltage range of the electronic product, please stop using the charger or mobile power supply. Packing list: 1 x USB Test Meter