Sierra 18-6099 Mercruiser Alpha Magnesium Anode For Mercruiser Alpha One Gen II 1991 Up. For fresh water use only. Material Magnesium For Alpha I 1991 up Interchangeable with Mercruiser Stern Drive 815933A1 821629A1 97-821629Q1 Application Mercruiser Stern Drive Alpha One Gen II 1998-2013 sn 0L100040 up Alpha One Gen II 1991-1995 sn 0D469859 thru 0F679999 California Residents WARNING Cancer and Reproductive Harm - P65Warnings.ca.gov Other Details Google Product Type Engine Parts Wiser Yes Pro