Description: Durable Material: The square hole drill fixed bracket is made of cast aluminum, 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 53cmx15cm/20.87inchx5.91inch. 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: 53cmx15cm/20.87inchx5.91inch Package Includes: 1 Square Hole Drill Bit Adapter 2 M3x0.5 screw Note: Please allow slightly errors due to manual measurement and different monitors.