USB Tester USB Power Meter 4-30V 0-5.1A Voltage Tester Multimeter USB Ammeter Tester IPS Color Display Voltmeter Ammeter Click the button to display the stored charging data in groups 1-9.Press and hold the button for 3 seconds to delete the charging data stored in one group. Quickly double-click the button to change the page that appears. Press and hold the button for a long time, then plug in, enter the voltage calibration as shown on the display: (5526V →), double-click the button again quickly as shown (5528V), and click the button to increase the displayed voltage. Quickly double click the button again, such as the display (5528V), click the button to lower the display voltage. Quickly click the button again to view (5526 →), then click the button to view the current calibration! The system automatically performs the current calibration. When the calibration is completed, it will automatically return to the main page of the function and can be used normally. Voltage: 4-30v Current: 0-6.5AMA: 0-999999 mAMWh: 0-9999999MWHas: 0-99 hours Power: 0-200w Charging Resistance: 0-999.9 ohms Grouping: 1-9 groups Indoor Temperature: 0-80 degree Size: 65x26x13mm Material: ABS+Metal Color: Black Package Content: 1 x USB Power Meter Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement error is +/- 1-3cm.