The RBX Interchangeable Hub seats to the propeller hub cavity in order to eliminate hub chatter and vibration while preventing spinning within the propeller. It features a one-piece rubber construction with anodized aluminum splines - no plastics to deteriorate. Hubs offer 10° deflection to reduce banging when shifting gears or hitting a submerged object. All RBX hubs are reusable if the propeller is damaged. Designed for use with the following: Evinrude/Johnson/BRP 40-75 HPLarge Gearcase1968 and Newer, 85-140 HP1969 and Newer 13 tooth spline with 4-1/4 Gearcase.