Jaw Coupling Hub, Coupling Size JC12, Outside Diameter 3/4 in, Coupling Overall Length 1 1/16 in, System of Measurement Inch, Hub Material Aluminum, Maximum Speed 8,000 RPM, Keyway Depth Not Applicable, Keyway Width Not Applicable, Bore Diameter 1/4 in, Shaft Locking Type Clamp On, Bore Type Round Bore, Jaw Profile Curved, Screw Thread Size M2.5, Bore Tolerance +0.002/-0.000 in, Fail Safe Yes, Shaft Tolerance +0.0000/-0.0005 in, Full Bearing Support Required Yes, Hub Diameter 3/4 in This product contains a chemical that is regulated under California Proposition 65. Warning: This product contains a chemical known to the State of California to cause cancer. Warning: This product contains a chemical known to the State of California to cause birth defects or other reproductive harm. -