Sacrificial anodes are specifically designed to protect parts of your personal watercraft that are underwater from galvanic corrosion. Like the name implies, they essentially ''sacrifice'' themselves by absorbing the electrochemical process of corrosion to prevent metal components like the impeller, jet pump nozzle or engine from being ''eaten away'' instead. Galvanic corrosion can cause major damage if not controlled. Inspect your sacrificial anode at least once a month. Replace it when it is 50% depleted. Outside diameter: 26 mm Height: 6 mm