Honda External Anode Metal - 41109-ZW1-B00. Important: Two required for each engine.. Help protect your Honda outboard from corrosion with the genuine Honda external anode metal, part number 41109-ZW1-B00. This sacrificial anode mounts on each side of the extension case and is designed to corrode first, reducing galvanic corrosion on more expensive engine components-especially in saltwater and brackish conditions.. Key Features. Genuine Honda external anode metal for corrosion protection. Two required for each engine. Mounts on each side of the extension case. Sacrificial design helps protect engine components from corrosion. Ideal for routine maintenance and preventative corrosion control. Fitment. Honda BF25A. Honda BF75AX through BF250D. Why It Matters. Anodes are designed to wear out over time. As the anode sacrifices itself, it helps reduce corrosion to more expensive metal components. Inspect anodes regularly and replace them when they show significant wear to help keep your Hond