Flo-Torq SSR Solid Propeller Hub Kit 8M0101603 fits select 200 hp through 400 hp Mercury FourStroke outboards with 1.25" propeller shafts. The SSR hub utilizes Quicksilvers proven Soft-Shift rubber technology to prevent shifting noise, vibration and harshness. SSR technology provides 22-23% reduction in shift event noise virtually eliminating shift clunk. Each kit includes the SSR drive sleeve, three-washer set (washer, thick washer and cupped Belleville washer), tabbed lock washer and locking prop nut. Installation is quick and easy with the Quicksilver floating prop wrench and Quicksilver Prop Block or common shop tools. Mercury FourStroke outboards with serial numbers lower than 2B244273 must see your dealer for an updated engine calibration before using this hub kit. 40 hp CT through 225 hp Mercury FourStroke outboards with 1" diameter propeller shafts used in general purpose and non-surface piercing propeller application installations use the SSR hub kit 8M0150152. 40 hp CT through 225 hp Mercury FourStroke outboards with 1" diameter propeller shafts used in high performance and/or surface piercing installations and 250 hp through 350 hp Mercury FourStroke outboards, use the SSR Solid hub kit 8M0101604. 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.