Checking the serial number of Earth Tester FT6031-50

QHow do you check the serial number of Earth Tester FT6031-50.

A

The serial number label of the Earth Tester FT6031-50 can be found on the front side of the instrument after removing the blue-colored protector.
In addition, when you turn on the instrument power while pressing the "3P/2P" button, the serial number will appear as shown in the figure.