Aluminum anode kit 8M0137814 is for use on the anti-ventilation plate on Mercury 175-300hp and 450R 3.4L V6 and 4.6L V8 4-stroke outboards (serial No. 2B529482 & above) and 5.7L V10 350hp and 400hp Verado Outboards. These aluminum anodes are for fresh water or salt water use. The anodes are important in the prevention of corrosion of aluminum or stainless steel engine parts. Inspect anodes periodically for best protection and replace when seeing signs of corrosion or pitting. Never paint an anode. See your owner's manual or service manual for specific applications and replacement instructions.