[Fitment]: The square hole drill bit adapter is suitable for hand electric drills, but NOT suitable for bench drills and rechargeable hand drills. [ Material]: The square hole drill fixed bracket is made of high quality cast aluminum material, wear , high hardness, sturdy and . [Note]: The square hole drill bit fixing bracket supports the exposed clamping part of the electric hand drill 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 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., Manufacturer: Akfldms