JKP 160-J6 High Precision Keyless 16mm ChuckMfr #: 9685D High precision model taper mounted industrial keyless chuck Precision tested and certified to 0. 0016 inches T. I. R max at half capacity Self tightening feature automatically increases gripping force proportional to increased torque to prevent tool shank slippage All components exposed to wear are completely hardened to maintain accuracy and extend chuck life 4 13 64 inches closed length