UniKey: Earthing Connection Product Tester. The optional Earthing™ Product Tester checks the conductivity of your Earthing products and ground cords to determine that they are conductive and in good working condition.
How It Works:
Simply connect the tester to the ground port of a properly grounded wall outlet and place it directly on your Earthing product. A green light will confirm that your product and wire are in good working order.