Mercruiser Zinc Trim Tab Anode | Canada Metals CM822157C2Z Martyr Zinc anode designed to protect gearcase from corrosion salt water. Mercruiser trim tab anode Zinc anode for salt water applications For F25 4-stroke carb models, F30 4-stroke (0G76033-1B226999 and 0P094500-0P400999), F40 4-stroke 3 Cylinder (0G760300-1B344398 and 0P094500 and up), F40/50 4-stroke (935cc, standard gearcase) Zinc aftermarket direct replacement for Mercury 822157T2