1.HSS Titanium Coating: Classic HSS construction with titanium coating for capability and durability. The cutting edge is hardened and honed for sharpness, chatter- design with staggered cutting teeth ensure the precise countersinking and hole smooth clean. It can be used multiple times without deformation 2.Wide Usage: The 135° fast cutting point is automatically centered and penetrates quickly with less pressure, the drill kit meets all your requirements, ideal Drilling in Wood/Cast Iron/Aluminum Alloy/Plastic/Fiberglass 3.Product Size: Including 16 pcs 1.5mm bits, 16 pcs 2.0mm bits, 15 pcs 2.5mm bits, 10 pcs 3.0mm bits, 10 pcs 3.2mm bits, 8 pcs 3.5mm bits, 8 pcs 4.0mm bits, 3 pcs 4.5mm bits, 3 pcs 5.0mm bits, 2 pcs 5.5mm bits, 2 pcs 6.0mm bits, 2 pcs 6.5mm bits, 2 pcs 8.0mm bits, 2 pcs 10.0mm bits 4.Convenient Access: Various sizes are placed in different compartments of the plastic box, and the corresponding sizes of different drills are printed on the bottom of the lid, making it very convenient to access