Features:Easy to use and install Conveniently, safely & quickly Easily locks onto and releases drill bits Keyless chuck finger-tightens for easy bit changes Universal chuck Mini Quick Change Keyless Chuck Allows drive power tools to use conventional drill bits Unlimited Use in Automotives, Garages, Warehouses, Offices, Homes Etc Instantly convert impact driver to hold non-quick change drill & driver bits Chuck allows quick and easy accessory changes without changing collets Easy to use and install. Specifications:Range : 0.3 to 3.2mm Material: Aluminium alloy Pitch : 0.75mm Model : M8x0.75 (long) , M8x0.75 (short) , M7x0.75 (long) , M8x0.75 (short) How to choose the length of the chuck:1.The meaning of the M7x0.75/M8x0.75 , M7/M8 refers to the grinding machine shaft outer diameter is 7mm/8mm, 0.75 is screw thread pitch is 0.75mm, your grinding machine shaft outer diameter measurements is 7mm or 8mm, you can consider it.2.If your drill rod diameter is relatively small,you can choose the long type3.If your drill rod diameter is relatively large size (close to 3.2mm), long and short also can be used. Package Content:1 x Mini drill chuck