- HSS Titanium Coating: Classic HSS construction with titanium coating for durability and wear resistance. The cutting edge is hardened and honed for sharpness. A staggered tooth design reduces chatter, delivering precise countersinking and smooth holes. It stays true with use and can be used multiple times without deformation. - Wide Usage: 135 degree fast-cutting point is self-centering and penetrates quickly with less pressure. Suitable for drilling in wood, cast iron, aluminum alloy, plastic, and fiberglass. - Product Size: Contents include 16 pcs of 1.5 mm, 16 pcs of 2.0 mm, 15 pcs of 2.5 mm, 10 pcs of 3.0 mm, 10 pcs of 3.2 mm, 8 pcs of 3.5 mm, 8 pcs of 4.0 mm, 3 pcs of 4.5 mm, 3 pcs of 5.0 mm, 2 pcs of 5.5 mm, 2 pcs of 6.0 mm, 2 pcs of 6.5 mm, 2 pcs of 8.0 mm, and 2 pcs of 10.0 mm. - Convenient Access: The bits are organized in a plastic box with separate compartments. The corresponding sizes are printed on the bottom of the lid for quick identification and easy retrieval.