2 PCS 79953Q04 Marine Lower Unit Oil Drain Plug Screw and Gasket Fit Mercury MerCruiser I R MR Alpha 1 TR TRS and All O/Bs with 3/8-16 non-magnetic Replaces 816610A1 28634 79953 18-2244

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, 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: Mercury 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.