STEEL ALLOY;INTERNAL SPLINE 10 PITCH 40 TEETH 20 DEGREE PRESSURE ANGLE PITCH DIA 4.000 IN.;EXTERNAL SPLINE 16/32 PITCH 152 TEETH 30 DEGREE PRESSUREANGLE PITCH DIA 9.500;OD MIN 9.543 IN.MAX 9.548 IN.;THK MIN 0.428 IN. MAX 0.443 IN.;HUB OD MIN 4.7487 IN. MAX 4.7495 IN.;ID MIN 3.940 IN. MAX 3.945 IN. CASE HARDNESS ROCKWELL C 49;CORE HARDNESS ROCKWELL C 31