[High-quality materials]: The square hole opening bracket is made of all-aluminum, which is wear-, hard, long-lasting and . [Efficient and convenient]: Professional woodworking tools, the square hole drill adapter bracket can help open square holes in seconds, greatly improving woodworking efficiency, and is a powerful helper for woodworking. [Easy to operate]: It is easy to open square holes with this tool. You can quickly install or disassemble it yourself. It is fast and convenient, and even beginners can easily get started. [Universal Design]: All square hole drill bits are universally designed and suitable for 38-43mm electric drill chucks. The clamping diameter is unified to 19mm, which helps accurate and smooth drilling. [Wide Application]: Professional woodworking tools, most hand drills can use this bracket, but rechargeable drills (lithium series) and bench drills are not suitable for this bracket. Precision square hole drilling tools, suitable for making mortise and tenon structures to achieve a firm connection. Colour:Silver Material:Aluminum Package Contents: 2x Square hole opening bracket Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.