Motion Control Coupling Hub, Angular Misalignment 0.5 Degrees , Axial Motion 0.2 mm, Coupling Size MOCT51, Outside Diameter 50.8 mm, Over-Standard Parallel Misalignment 5.08 mm, Parallel Misalignment 0.25 mm, Coupling Overall Length 59.7 mm, Hub Material Aluminum, Length through Bore 20.8 mm, System of Measurement Metric, Bore Diameter 20 mm, Maximum Speed 4,500 RPM, Bore Type Round, Shaft Locking Type Clamp On, Keyway Depth Not Applicable, Keyway Width Not Applicable