Jacobs 6219 2BA Medium Duty Plain Bearing Keyed Chuck 1.0 to 10.0 Millimeter Capacity With 3/8-Inch 24 Threaded Mount High accuracy T.I.R. 0.004-Inch maximum at half capacity Jaws center-ground for absolute straightness and alignment One-piece sleeve eliminates crack between driving teeth often found in other designs Through-hardened sleeve teeth, plus hardened nose and keyholes provide outstanding wear resistance Each chuck 100-Percent inspected for performance and precision