Material: high speed steel with titanium coating. Drills are smoothed and coating, these drill bits are evenly and sharp, HSS steel fast and durable. 6 different diameters for choice, metal drill diameter: 1mm 1.5mm 2mm 2.5mm 3mm 3.5mm, each size 10 pcs. Titanium coating Improve the surface hardness of the bit, improve the machining accuracy, improve the surface quality of the bit, reduce the coefficient of friction with the workpiece processing, improve the wear resistance. Suitable for drilling holes in a variety of surfaces including aluminum, wood and plastic,Ideal for DIY, craft project and general building/engineering use. Features: High Speed Steel, Durable.with Titanium finish that will help them last longer holes. Pre-drilling keeps wood from splitting before putting a screw in it and makes adding hardware go much smoother. Holds stripping screw heads. Normally or bits are stored in cases by size and it would be difficult to find the correct drill bit, this is very easy to choose the correct bit with calipers and we checked the diameter before using They are very useful in doing some type of DIY, craft project and general Building/Construction Use, it can be used to drill holes in a variety of surfaces including metal, wood and plastic. Contained sizes: 1mm,1.5mm,2mm,2.5mm,3mm3.5mm Size and quantity: 1.0mm: 10 pieces 1.5mm: 10 pieces 2.0mm: 10 pieces 2.5mm: 10 pieces 3.0mm: 10 pieces 3.5mm10 pieces Quantity: 1 Set (60 pieces)