Mercury - Quicksilver Magnesium Anode Assembly Corrosion Protection 35-300HP Outboards & MerCruiser Drives 76214A6. Overview. If you boat primarily in freshwater, magnesium anodes offer the best protection money can buy. The Mercury Marine 76214A6 Quicksilver Magnesium Anode Assembly protects your Mercury and Mariner 35-300HP outboards, as well as MerCruiser Alpha One Gen II and Bravo I, II, and III sterndrives, from corrosion. It's also compatible with Force 90 and 120HP outboards (1995 and new