Martyr CMP-06, Rudder / Trim Tab Disc Anodes, Stainless Steel Allen Head Zinc alloy for use in saltwater, aluminum alloy for use in salt & brackish (mixed) water or magnesium alloy for use only in fresh water Martyr Anodes offer maximum protection by maintaining quality alloys, free from impurities like iron, which can compromise performance Provides low cost cathodic protection of ocean-going vessels, structures and equipment constructed of iron, steel, aluminum, magnesium, and other metals High-quality Martyr anodes are pressure diecast and manufactured to strict quality standards through an ISO 9001 Quality Management System