UNIQUE DESIGN: The unique thrust bearing can convert the torque applied by the drill bit into a higher clamping force. In addition, the jaws match very precisely, so that the drilling tools will not loosen due to vibrations or shocks. There are signs of " Grip " and " Release " on the top of the device, which can guide the bit installation correctly and prevent malfunction. SUPERIOR QUALITY MATERIAL: The chuck is forged from high quality steel, with high hardness, not easy to break, high precision, strong and durable. Black rubber sleeve eliminates the possibility of rust, and its compact body and its ergonomic design are more suitable for transport and rotation. ADVANTAGES: The chuck drill is convenient and quick to use when you need to change drills of different specifications. It is flexible to use and can change various electric drill bits at will. A simple accessory can allow your machine to perform multiple functions, thus eliminating the money and time of purchasing multiple tools. HOT TIPS: Do not use it counterclockwise. Please check if this light is suitable for your electric hand drill before purchasing. Specific parameters and size data have been marked in the image and description. WIDE APPLICATION: This keyless drill chuck is a multi-functional product, suitable for almost all brands of electric hammers and wrenches. It can quickly replace drill bits of different specifications to facilitate operations drilling in different conditions and materials. Specification: Threaded mounting: 1/2 " -20 UNF Chuck adapter thread: 1/2 " Clamping range: 2-13 mm Size: shown as pictures Package weight: approx. 260g / 9.2oz List of packages: 1 drill chuck 1 chuck adapter Note: Please allow slight error due to manual measurement. Thank you for your understanding.