Size: 1/4inch (6.4mm), 5/16inch (8mm), 3/8inch (9.5mm), 1/2inch (12.7mm), 5/8inch (16mm), 9/16 inches (14 mm) Made of high-speed steel, heat treatment, high hardness, long core, high concentration. Note: The square hole drill must be used in conjunction with the square hole drill (mortise and tenon), and cannot be used with electric drills and bench drills The pressure is less when drilling, which reduces the labor intensity of construction workers, accelerates construction speed, reduces construction costs, and is suitable for installation and decoration industries. Our woodworking planing bit is suitable for drilling holes in wood with a tongue and groove machine or tongue and groove attachment, and has a long service life, please use it with confidence. Color: Silver & Black Material: carbon steel Package Contents: 6 x square hole drill 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.