Heavy duty design. Special quenching treated key parts increases durability. Suitable for drill presses or lathes spindle accepts R8 shank Jaws are specially engineered to achieve balance. JT33 mounted. Chuck key and R8-JT33 arbor are also included in the package. Please note, we have pre-installed the arbor to the drill chuck and lubricated together againsting rusty. For first time use, please uninstall the arbor and drill chuck and clean the lubricate to prevent the possible slippery.