Abstract: The invention is directed to a mountable electrode, methods for preparing said mountable electrode, a method for monitoring the corrosion protective properties of a coating on a metal substrate, a method for measuring the corrosion rate of an uncoated metal substrate, an apparatus for measuring electrochemical impedance spectroscopy of coated metal substrates, and the use of said mountable electrode. The mountable electrode of the invention comprises -a carrier comprising a water-soluble layer, wherein said water-soluble layer comprises a water-soluble polymer; and -a water-permeable pattern of an inert metal on said water-soluble layer.