Features 1、Twist drill bits are made from high speed steel for high hardness and durability 2、The surface of drill bit is coated with black oxide to add mild corrosion resistance 3、There are 15 pieces drill bit in three sizes of 3.0mm, 4.0mm, 5.0mm, five pieces for each size 4、They are great for most drilling jobs and materials such as aluminum alloy, iron, wood, plastics 5、Sharp twisted drill bits will make the drilling easier and more effortless Specification Features: Twist drill bits are made from high speed steel for high hardness and durability. The surface of drill bit is coated with black oxide to add mild corrosion resistance. There are 15 pieces drill bit in three sizes of 3.0mm, 4.0mm, 5.0mm, five pieces for each size. They are great for most drilling jobs and materials such as aluminum alloy, iron, wood, plastics. Sharp twisted drill bits will make the drilling easier and more effortless. Specifications: Material: High speed steel Surface Finishing: Black oxide Type: Twist drill bit Size: 3.0mm, 4.0mm, 5.0mm Quantity: 5 pcs each size Hex Shank Diameter: 7mm Package Includes: 15pcs x Drill Bits Package List