Sierra 18-3221 Mercruiser Alpha Gen II Water TubeSierra high-quality replacement water tube for Mercruiser Alpha Gen II Cooling Systems.Interchangeable with: GLM; 12829; Mallory; 9-44010; Mercruiser Stern Drive; 32-860220; 32-814384; Application:Mercruiser Stern Drive Alpha One Gen II; 1998-1998; s/n 0L100040 & up; Alpha One Gen II; 1991-1995; s/n 0D469859 thru 0F679999; Alpha One Gen II; 1996-1997; s/n 0F680000 thru 0K999999;