You'll get top quality with the Mercury® Marine® Quicksilver® Gear Case Drain Plug Screw Kit. This drain plug screw and O-ring bring unbeatable durability for long-lasting use. The Mercury Marine Quicksilver Gear Case Drain Plug Screw Kit fits Mercury MerCruiser® I, R, MR, Alpha One, TR, TRS, and all outboards with non-magnetic gear lube or vent screw. Manufacturer model #: 10-79953Q04. Durable gear case drain plug screw kit. Flathead-screwdriver top. Fits Mercury MerCruiser I, R, MR, Alpha One, TR, TRS, and all outboards with non-magnetic gear lube or vent screw.