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: Yamaha T25 HP (2010 and Newer), F30 (4-Stroke) (2001-05), F40 (4-Stroke) (1999 and Newer), F50 (4-Stroke) (1995 and Newer), F60 (4-Stroke) (1999 and Newer), 40 HP and 50 HP (not T50) (1984 and Newer), 48 HP (1995-00), 55 HP (1976-95), 60 HP (1976-91) (not T60); 13 tooth spline, 3-1/2" Gearcase.