The Martyr CMC12 zinc shaft donut anode provides effective and affordable cathodic protection for ocean-going vessels and marine structures made from iron, steel, aluminum, magnesium, and other metals. Designed for use in saltwater applications, it is ideal for pleasure craft but not recommended for freshwater environments. This anode is made from military-spec zinc alloy and is pressure die-cast to meet strict ISO 9001 quality management standards, ensuring long-lasting performance and corrosion resistance in harsh marine conditions.