Features 1. Material: The square hole drill bit is made of bearing steel, which is sturdy and durable. 2. Drill Bit Accessory: A square hole drill bit adapter for desktop drilling machines, convenient for installation and use. 3. Easy To Install: The converter is easy to install and remove, allowing you to quickly install or remove it yourself, saving you time and energy. 4. Effective And Precise: The adapter ensures accurate and smooth drilling operations. Includes four square hole drill bits: 6mm (1/5 inch) 6.4mm (1/4 inch), 8mm (5/16 inch), 9.5mm (3/8 inch) 5. Usage: Suitable for wooden products such as density board, medium fiber board, particle board, wood, etc., suitable for square hole drilling machines. Specification Material: Bearing steel Color: Silvery Size: 23.5 x 22.8 x 4 cm Weight: 760 g Package Include: 4 Piece Set Square hole drill bit for woodworking