Features: Our center drill bits are selected from High-speed steel, solid and high-temperature wear-resistant. Entire center drill bit set contains 7 drill bits of different sizes from 1/1.5/2/2.5/3.5/4/5mm to meet different needs. Drills can be used to process centering holes and countersinks of general materials, and can also be used to process center holes on the end faces of shafts and other parts. Reasonable angle drills precise tapered holes in metal processing, which makes the positioning more accurate, reduces errors and makes drilling more efficient. Double-head design, both ends can be used for cutting, cost-saving, convenient and fast, straight shank, convenient disassembly, and assembly. Specifications: Component:Steel Size:Approx.1mm/1.5mm/2mm/2.5mm/3.5mm/4mm/5mm Package Includes: 7Pcs Center Drill Bits note: 1.Please allow 1-2cm errors due to manual measurement, making sure that you not mind before order. 2.Due to the differences between different monitors, the picture may not reflect the actual of the item.