Mercury - Quicksilver Zinc Trim Tab Corrosion Protection & Steering Aid Cast Zinc 34127T2. Overview. Steering control and corrosion protection go hand in hand with the Mercury Marine 34127T2 Quicksilver Zinc Trim Tab. Designed for MerCruiser R, MR, and Alpha One sterndrives, this trim tab helps offset propeller torque for smoother handling while protecting your drive from galvanic corrosion. Made from high-quality zinc, it's built for both fresh and saltwater use, providing reliable protection a