Adjustable Drilling Length: can be adjusted for different screw lengths simply by loosening and tightening the set screw. Multi-size: one tool for multiple uses, our 5 types taper drill bit set of sizes: 2.8 x 8mm/3.0 x 8mm/3.2 x 8mm/3.5 x 8mm/4 x 8mm to meet your needs. Premium Material: made of high quality alloy steel.It is very suitable for drilling holes in wood of various sizes. A versatile tool, improves work efficiency. Usage: Compatible with drills with chuck, for drilling on wood or parquet, for DIY, home and general construction or engineering use etc. Efficiency: spiral flute with center drill will quickly unload chips from the hole, the five-edge chamfer design effectively prevents accumulation of debris and improves drilling efficiency Feature: Stored in a sealed package with good protections. < p>Specially used on metal and steel plate, gives fast and easy cutting. Suitable for woodworking. Drilling and countersinking for wood screws without changing drill bit. Counter-sleeve adjustable in depth with an Allen key. Precautions: 1. Check integrity of hole opener before use and tighten hole inserter when loading drill. 2. When working, the hole opener should be perpendicular to the workpiece. 3. After positioning, the propulsion force is given slightly during the drilling process. 4. When drilling, the rotation speed should not be too low, thus preventing the blade from jamming and causing chipping. 5. Coolant should be added during the opening process to prevent damage from excessive temperature. Specification: Name: Drill Bit Blade Set. < p>Material: YG8 alloy. Color: silver and orange. Dimensions: 2.8x8mm/3.0x8mm/3.2x8mm/3.5x8mm/4x8mm. Stem Type: Round. Stem Diameter: 8mm. (Note: Please allow 1-3mm error due to manual measurement and slight color difference due to light and screen.) Note: The data is manual measurement, please allow 1-3cm error, due to differences between light and screen, there will be a certain color difference, the specific received in nature prevail.