Mercury - Quicksilver 821630Q1 Aluminum Drive Shaft Housing Anode MerCruiser Bravo I, II, III, X, XR & XZ Drives 821630Q1. Overview. Corrosion never takes a break, but the Quicksilver 821630Q1 Aluminum Drive Shaft Housing Anode keeps your MerCruiser Bravo sterndrive one step ahead of it. Cast from high-quality aluminum, this OEM anode is built to protect your drive and engine from the harmful effects of galvanic corrosion - in both saltwater and freshwater.. It installs at the bottom of your dri