Lower unit gear lube drain and fill hole screw and seal 79953Q04 is used with 3/8-16 drain/fill hole screw on all MerCruiser sterndrives, Mercury and Mariner outboards except the Verado series. 

It is very important to use the seal to make sure the drain/fill hole screw seats properly to retain the gear lube in the gear case and keep damage causing water out of the gear case.

• Used with 3/8-16 drain and fill hole screw on all MerCruiser sterndrives, Mercury and Mariner outboards except the Verado series

• Must use this seal to properly seat the drain/fill hole screw in the lower unit

• Helps prevent gear lube from leaking out and water from seeping in to the gear case causing serious damage

• This is the non-magnetic plug screw version