General description 120pcs Twist Drill Bits set includes high-speed steel (HSS) titanium micro drill bits in six different diameters: 1.5mm, 2mm, 2.5mm, 3mm, and 3.5mm. Each size has 20 pieces, providing a total of 120 bits to meet various drilling needs. Technical specifications Material: High-speed steel (HSS) with titanium surface treatment Sizes: 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm Quantity: 20 pieces per size Usage Suitable for drilling into aluminum, iron, wood, and plastic Ideal for DIY projects, craft applications, and general construction tasks