"The SOLAS RBX-B30 Rubex Propeller B2-Series Interchangeable Hub Kit seats tightly to the propeller hub cavity to eliminate hub chatter and vibration. Its built-in 10 deflection reduces banging when shifting gears or when hitting a submerged object. Reusable if propeller is damaged. Hub will not spin in propeller. Anodized aluminum splines (some available in bronze). 1-piece rubber construction with no plastics to deteriorate. Interchangeable with Mercury Flo-Torque and Michigan Vortex propellers. All necessary hardware included. 10-tooth spline and a 3"" gearcase. This boat propellor hub kit from SOLAS fits with the following Mercury/Mariner/MerCruiser applications: 25hp 80-84, 28hp 76-79, and 30hp 79-90. It also fits with these Yamaha applications: 20hp 96-97, F20 (4 stroke) 18 and newer; F25 (4 stroke) 98-06; 10 and newer, 25hp 80 and newer; and 30hp 1979-2002.Manufacturer model #: RBX-B30. Seats tightly to eliminate hub chatter and vibration 1-piece rubber construction Built-in 10 deflection All hardware included"