Magnesium Anode Kit | Martyr CM818298KITM Martyr power trim and transom bracket anode protects trim cylinder from corrosion in fresh water lakes and rivers. Martyr Magnesium Anode Kit | CM818298KITM Mercury power trim anode For Mercury/Mariner 30/40 Fourstroke, 40 4 Cylinder, 50 3 cylinder 1987-1997, 55 3 cylinder, 60-90 3 cylinder 1987 and newer, 75 4 cylinder, 75/90 4-stroke, 100-125 4 cylinder, 115 6 cylinder 1984-1988 and all V6 and OptiMax outboards Magnesium anode for use in fresh water applications 7 1/2 in. long x 2 in. wide Found on the bottom of external power trim pump assembly or transom bracket Magnesium replacement for Mercury's aluminum anode p/n 97-818298q1 For magnesium anode with hardware see p/n CM818298KITM For aluminum see p/n CM818298A For zinc see p/n CM818298Z