DERMAVIT Diamond Shield IE Professional Bedienungsanleitung Seite 42

An earthing cable and an enclosed power socket tester are included in the scope
of supply. The good effect of the earthing (so called negative ions) occurs only if
the power socket is properly earthed. Be sure to check this with the power socket
tester.
Warning
The use of the earthing plug (or any other electrical appliances) to an incorrect
power socket can be perilous.
Do not use the earthing cable during a thunderstorm.
Diamond Shield IE Professional
page 42
Instruction Manual