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
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.