Mercury - Quicksilver Aluminum Square Anode Set Corrosion Protection Kit Cast Aluminum 42121Q02. Overview. Corrosion can sneak up fast in any water, and the Mercury Marine 42121Q02 Quicksilver Aluminum Square Anode Set helps stop it before it starts. This set of two anodes is designed for a range of Mercury, Mariner, and Force outboards, including popular 6-15HP models. Made from mil-spec cast aluminum, these anodes protect your gearcase and other underwater metals from galvanic corrosion in bot