Description: Durable Material: The square hole drill fixed bracket is made of high quality cast aluminum material, wear resistant, high hardness, sturdy and durable. Fitment: The square hole drill bit adapter is suitable for hand electric drills, but NOT suitable for bench drills and rechargeable hand drills. Note: The square hole drill bit fixing bracket supports the exposed clamping part of the electric hand drill with a width of about 20mm/0.79inch and a diameter of 38mm-43mm/1.50inch-1.69inch. Please confirm the size carefully. Easy to Use: Professional woodworking tool, the square hole drill bit adapter bracket helps ensure accurate and smooth drilling. Easy Installation: The square hole drill bit adapter mortise tool is easy to install and remove, you can quickly install or remove it yourself, fast and convenient. Specification: Product size: 5.3cmx15cm/2.09inchx5.91inch Material: cast aluminum Package Includes: 1Square Hole Drill Bit Adapter Note: Please allow slightly errors due to manual measurement and different monitors.