125 in, Hub Material Aluminum, Length through Bore 0.5 Degrees , Axial Motion 0.39 in, System of Measurement Inch, Bore Diameter 5/16 in, Maximum Speed 4,500 RPM, Bore Type Round, Shaft Locking Type Set Screw, Keyway Depth Not Applicable, Keyway Width Not Applicable.008 in, Coupling Overall Length 1.