This drain plug seal kit includes screw and gasket, non-magnetic, mainly to prevent gear lube from leaking out and water from seeping in to the gear case causing serious damage. This lower unit gear lube drain kit used with 3/8 - 16 drain or fill hole screw of all MerCruiser stern drives, for Mercury and Mariner outboards EXCEPT THE VERADO series Broad Application: Detailed fit for MerCruiser I R MR Alpha 1 TR TRS and all outboards Compatible with following OEM part numbers: Marine 20259 28634 28634A1 79953 79953A2 79953Q04 79953Q2 Mercruiser Stern Drive 19183 191832 191833 19183B 20260 20260B Johnson/Evinrude Outboard 307552 Mallory 60101 60102 Chrysler/Force/US Marine 19183 F50556 F8077 F8186 Easy installation: Pump the oil in from the bottom plug, till it comes out of the top one, tighten the top plug then quickly screw the bottom plug in to minimize oil loss. This new aftermarket lower unit drain plug seal kit designed to minimize oil loss. OEM quality aftermarket replacement part, meets or exceeds OEM specifications Quantity: 2 Replaces: Chrysler/Force/US Marine 10-79953 10-79953A2 10-F50109 F40109 GLM 22420 Mallory 9-72650 Mercruiser Stern Drive 10-28634 10-28634A1 10-79953 10-79953A2 10-79953Q04 10-79953Q2 816610A1 816610A2 for Mercury Marine 10-20259 10-28634 10-28634A1 10-79953 10-79953A2 10-79953Q04 10-79953Q2 18-2945 Chrysler/Force/US Marine 12-19183 F50556 F8077 F8186 Johnson/Evinrude Outboard 307552 Mallory 9-60101 9-60102 Mercruiser Stern Drive 12-19183 12-191832 12-191833 12-19183B 12-20260 12-20260B for Mercury Marine 12-19183 12-191832 12-191833 12-20260