Grizzly G9865 - 6" 4-Jaw Plain Back Independent Chuck
"Independent” means that each jaw moves independently. Such 4-jaw chucks are used for holding odd shaped pieces or where zero tolerance is required. These 4-jaw chucks have semi-steel bodies and hardened reversible jaws. Requires a back plate to mount to your spindle. Bore: 2 1/8"
Note: The mounting holes for this specific chuck are through the back.