Square Hole Drill Bit Adapter and 4 Drill Bits for Drill Press Hollow Chisel Mortise Drill Tool Square Hole Drill Bit Set: Includes 1 square hole bit adapter and 4 square hole drill bits. Compatible with bench drills and hand drills with clamp diameters ranging from 38 to 55 mm (1.5 to 2.2 inches) for easy installation. Note that this product is only suitable for bench drills and hand drills equipped with clamps. Quality Materials: The square hole drill bit adapter is made of high-quality steel, strong and durable, designed to firmly secure wood. The mounting diameter is precision machined for accurate fitting with various mortise accessories, reducing operational errors. Specially designed to prevent blockage from wood chips during cutting. High hardness, non-slip design, sharp cutting edge for efficient performance. Handle with care when removing. Efficient and Accurate: The bit adapter and included drill bits come in 4 sizes for versatile use. Precision-engineered design ensures accurate mortise hole drilling, offering a faster and more convenient alternative to traditional mortise machines. Widely Applicable: This adapter helps reduce labor intensity and improves work efficiency. Ideal for construction, carpentry, DIY projects, and interior decoration. Suitable for low-hardness materials such as compressed board, plastic, particleboard, sandalwood, pine, ash, and similar woods. Dual Support Bracket: Wood square hole drill bits are reliable and functional, compatible with bench and hand drills. The adapter is ideal for woodworking, furniture manufacturing, and related applications. Note: Minor color variations may occur due to lighting and display differences. This does not affect product usability. Material: Steel Color: As shown Package Contents: 1 x Square Hole Bit Adapter 4 x Square Hole Drill Bits Note: Only the items listed above are included. Other accessories are not part of the package. Note: Lighting and screen settings may cause slight color differences between the image and the actual item. Measurement may vary by +/- 1-3 cm.