Gear case gear lube drain screw washer 8M0183616 is rubber coated stainless steel that fits Mercury and Mariner outboards and all MerCruiser sterndrives with 3/8-16 gear case drain/fill screw holes. Always double check to make sure the washer has been secured when reinstalling the drain screw. Water could infiltrate the gear case without it and cause catastrophic damage to the gear case. Keep spares on hand to ensure placement after changing gear lube in gear case. See your owner's manual or service manual for specific applications and replacement instructions. The Quicksilver brand is the leader in delivering uncompromising engine oils, parts and accessories to the marine industry for over 65 years. Quicksilver is the premier supplier of Mercury Marine Original Equipment replacement engine parts, oils, and accessories, but also works to serve all Original Equipment brands in the marine and powersports industries. It has earned a loyal following by providing the highest quality products that are tested through some of the most rigorous environments and testing procedures. No aftermarket company comes close to the level of research and design as Quicksilver; buying Quicksilver is buying performance, protection and peace of mind.