Mercury Marine® Drain Plug Seals are made of stainless steel that's been rubber coated to create a leak-free seal. Made to fit Mercury® and Mariner® outboard motors, and these versatile seals even match up with all MerCruiser® stern drives with 3/8-16 gear case drain/fill screw holes. These drain plug seals from Mercury Marine are so useful, you might want to keep a couple spares on hand to easily replace worn seals after changing the gear lube inside the gear case. Produced to the strictest standards and specifications to maximize and protect the performance of your boat motor. 4 pack. Stainless steel is rubber coated for a leak-free seal. Fits 3/8-16 gear case drain/fill screw holes. Works with Mercury and Mariner outboard motors. Matches all MerCruiser sterndrives. Produced to strict standards.