Quicksilver 34127T2 Zinc Trim Tab for MerCruiser R, MR and Alpha One SterndrivesZinc Trim Tab 34127T2 is for use on MerCruiser R, MR and Alpha One series sterndrives.Engine Part Application:An optional trim tab for R, MR and Alpha One drives. Provides increased steering torque reduction for non-power steering applications. Will not work with Black Max or other high rake propellers.Key Product Features Zinc trim tab to offset steering torque in MerCruiser R, MR and Alpha One sterndrives; Not for use with high rake propellers; Inspect anodes periodically for best protection and replace when seeing signs of corrosion or pitting to help keep your maintenance costs down; For use in fresh or saltwater; Helps protect your drive from the harmful effects of galvanic corrosion.; Engine Part Supersedes 34127T1;