Description: 【Durable Material】: Fixed holder bracket for square hole drill is made of high quality aluminum steel material, wear resistant, high hardness, sturdy and durable. 【Fitment】: The square hole drill bit adapter converter is fit for table drill and hand drill clamp with a diameter between 38mm to 55mm/1.5 to 2.2inch 【Bench Drill Mortise Accessories】: Woodworking drill guide is easy to install and remove, you can quickly install or remove it yourself, fast and convenient. 【Note】: Square hole drill bit adapter, products do not include square hole drill and electric drill, dual use support bracket for table drill and hand drill. 【Wide Application】: Drill jig bracket is perfect for woodworking, ensuring accurate and smooth drilling. 【Drill Bit Specifications】: 6.4/8/9.5/12.7/14/16mm