5/8 Bore A 20000 RPM Maximum 3/16 Keyway 1.42 OD Lovejoy U-75R Shaft-to-Shaft Uniflex Coupling 3.31 Overall Length 3/4 Bore 175 in-lbs Max Torque 3/16 x 3/32 Keyways 5/8 Bore A 3/4 Bore 3/16 Keyway 1.42 OD 3.31 Overall Length 