1. Timing shutdown settings. Continue to click the button until the screen display appears on the right. Then press and hold the button for 3 seconds, the numbers on the screen will flash. Click the button again to increase the 30- shutdown delay. Then press and hold the button for 3 seconds to save your settings. 2. Overvoltage protection settings. Continue to click the button until the screen display appears on the right. Then press and hold the button for 3 seconds, the numbers on the screen will flash. Click the button again to increase 0.5 volts. Then press and hold the button for 3 seconds to save your settings. 3. Overcurrent protection settings. Continue to click the button until the screen display appears on the right. Then press and hold the button for 3 seconds, the numbers on the screen will flash. Click the button again to increase 0.5A current. Then press and hold the button for 3 seconds to save your settings. 4. Return to the main page, press and hold the button for 3 seconds to clear the saved data such as accumulated working time, power, and energy. 5. Current and voltage calibration : use 5.000V standard voltage. Press and hold the button until "Factory Settings" appears on the LED screen. It will automatically calibrate. 1. Voltage: DC 4V-30V (overvoltage protection can be set) 2. Current: 0-5.5A (overcurrent protection can be set.) 3. Power: 0-150W 4. Power: 0-99999mAh 5. Energy: 0-999.9mWh 6. Timing: 0-99 hours 7. Countdown: 0-24 hours 8. Charging resistance: 0-999.99 9. Current/Temperature 10. Data output voltage 11. Power supply voltage Material:plastic colour:White Package Contents: 1 x Voltage Current Tester Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.