ITEM NAME:1/4 inch Impact Drive Hex Shank Quick Release Change Holder Bit Drill Chuck E4T1 1/4 inch Impact Drive Hex Shank Quick Release Change Holder Bit Drill Chuck E4T1.The interface has a locking function: it will be self-locked while a drill bit connect to it, grip the black chuck by your one hand and push the hex shank by your another hand, then the connecting drill bit can be pulled out.