Description: 【Material】The square hole drill fixed bracket is made of quality aluminum casting, wear resistant, high hardness, sturdy and durable. 【Fitment】The square hole drill bit adapter is suitable for most of the 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 square hole drill bit adapter bracket helps ensure accurate and smooth to drill. 【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. Size Chart: approx 5.3cmx15cm/2.09inchx5.91inch Package Includes: 1 Square Hole Drill Fixed Bracket Note: Please allow slightly errors due to manual measurement and different monitors.