Sierra 18-2945-9 Drain Screw Gasket 2 pack This Sierra 18-2945 Drain Screw Gasket is used with 38-16 drainfill screw found on all Mercruiser and most MercuryMariner OBs. This gasket is used in most lower units and sea water pumps. Sold as a 2 pack Interchangeable with ChryslerForceUS Marine 12-19183 F50556 F8077 F8186 JohnsonEvinrude Outboard 307552 Mallory 9-60101 9-60102 Mercruiser Stern Drive 12-19183 12-191832 12-191833 12-19183B 12-20260 12-20260B Mercury Marine 12-19183 12-191832 12-191833