Features: ● Material: the square drill hole is made of high-speed steel. After heat treatment, it has high hardness drill, sharp square chisel and long service life.● Size: provide 4 different sizes for your choice, 6mm, 6.4mm, 8mm, 9.5mm. These rectangular drill bit sets can meet most of your needs.● High working efficiency: wood drill parts set, long core and square chisel, easy to wrench holes in the wood, then you can quickly get various mortises. In addition, it can also save labor.● Available Applications: These woodworking countersunk chisels are suitable for drilling square holes in wood with a mortise machine or mortise mounting. In addition, it is suitable for electric drills, hammers and other tools.● Reduce the labor intensity of construction workers, speed up construction, and reduce construction costs in the construction, installation, decoration and decoration industries. Specification: Material: High Speed SteelColor: SilverSize1: Approx.61x133x19x6.5mm/2.4x5.2x0.74x0.25inchSize2: Approx.134x58x19x8mm/5.27x2.28x0.074x0.31inchSize3: Approx.118x41.5x19x6.4mm/4.64x1.63x0.74x0.25inchSize4: Approx.118x41.5x19x6mm/4.64x1.63x0.74x0.23inchPackage Included:1 x Core Drill BitNote: 1. Please allow 1-2mm errors due to manual measurement, please make sure you do not mind before ordering.2. Due to the difference between different monitors, the picture may not reflect the actual color of the item.