Voltage and Current Measurement: Connect the male USB plug to a 5V charger and the female connector to your mobile phone or other equipment to directly read voltage and current parameters. Measure MicroUSB Cable Quality: Connect your mobile phone, plug into a 5V charger, record the voltage. Then, insert the MicroUSB cable into the machine's MicroUSB port to record the voltage again. A smaller voltage deviation indicates a higher quality MicroUSB cable. Measure Mobile Power Output Capacity and Efficiency: Connect the mobile power supply to your phone, turn on the mobile power, press and hold the button until capacity data resets to zero. Then, charge your phone multiple times until the power automatically shuts off. The displayed capacity is the mobile power supply's output mAh when the device is next turned on. Note: This mAh is the raw data. Data Switching: Click the button to move to the next dataset, then double-click to move to the previous dataset. Clear Data: Press and hold the button for more than 3 seconds to clear group data.