IMPA 673501/673502/673503/673504 Zinc Anode Replacement Elements An easily replaceable zinc element for use in pipes which are continuously exposed to seawater.Serves to protect heat exchangers.piping, tanks.bumpandother hydraulic equipment from corrosion.The anode supplies a continuous protective current to eliminate the corosion current flowing from a metal surface. Has the same components as the MIL-A-18001-H U.S. A.