Mercury - Quicksilver 821630T1 Aluminum Drive Shaft Housing Anode MerCruiser Bravo I, II, III, X, XR & XZ Drives 821630T1. Overview. Salt, current, and moisture can quietly eat away at your drive's housing if left unprotected. The Mercury 821630T1 Aluminum Drive Shaft Housing Anode gives your MerCruiser Bravo sterndrive the corrosion defense it needs to stay in great shape. Designed for Bravo I, II, III, X, XR, and XZ drives, this OEM anode shields the drive and engine from galvanic corrosion in