The Martyr (Canada Metal Pacific) Part #CMR02 is a zinc sacrificial anode designed to protect boat rudders and trim tabs from corrosion in saltwater environments. Measuring 2-13/16 inches in diameter and 1/2 inch in thickness, this anode is constructed from high-purity zinc, ensuring effective protection against electrolysis and galvanic corrosion. It attaches securely using a stainless steel Allen screw, making it suitable for both saltwater and freshwater applications. Martyr anodes are known for exceeding U.S. Military Specifications, providing reliable and long-lasting corrosion protection for your marine components.