Honda Internal Anode Metal - 12155-ZV4-A01. Help protect your Honda outboard from internal corrosion with the genuine Honda internal anode metal, part number 12155-ZV4-A01. This sacrificial anode is designed to corrode first, helping reduce galvanic corrosion inside the engine and protecting more expensive internal surfaces and water passages in harsh marine conditions.. Key Features. Genuine Honda internal anode metal for corrosion protection. Sacrificial design helps protect internal engine components and water passages. Helps reduce galvanic corrosion in saltwater and brackish conditions. Ideal for preventative maintenance and routine corrosion control. OEM fit and function for compatible Honda applications. Fitment. Honda BF9.9A. Honda BF15A. Honda BF8D. Honda BF9.9D. Honda BF15D. Honda BF20D. Honda BF250A through BF250D. Why It Matters. Internal anodes are engineered to take the hit first, helping protect expensive internal metal surfaces and cooling passages from corrosion. Inspe