This square hole drill bit adapter adopts all-steel castings, which is sturdy and durable. It adopts precise design and easy to install and remove. This tool is suitable for clamping diameter ranges from 38 to 55MM/1.5 to 2.2 inches. Features: Quick Installation This square hole drill fixing bracket is high efficient to install and remove. It can ensure accurate and smooth drilling operations. Multifunctional Our square hole drill bit adapter is multifunctional and suitable for woodworking, furniture making and other related industries. It can save your time and energy.  Specification: Product Name: Square Hole Drill Bit Adapter Material: High Carbon Steel Lower inner diameter: 55mm Upper inner diameter: 19mm Clamp diameter ranges from 38 to 55MM/1.5 to 2.2 inches.  Color: Silver  Notes: 1.The product does not include square hole drills and electric drills. 2.If stored in a humid environment for a long time, it may cause some surface rust, just wipe some protective oil to improve it.  3.Lithium battery rechargeable hand drills are not suitable. 4.There may be slight differences between the picture and the actual color of the commodity. We will try our best to show you the exact color. 5.Please allow slight dimension difference due to manual measurement. Package Includes: 1×Electric Drill Tenoning Bracket  1×Screw