Set of 13 twist drill bits - Suitable for drilling holes with wood, plastics, metals (thin aluminum plate or thin iron). Not suitable for walls, stainless steel etc. Diameter set of 13 drill bits - 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.2mm 3.5mm, 4, 0mm, 4.5mm, 4.8mm, 5.0mm, 5.5mm, 6.0mm, 6.5mm. 6.35mm hex handle - Replace bit quickly and safely. Compatible with bench drill, ordinary manual electric drill or other standard drill chucks. Smooth drilling: designed as 45 outer edge angle angle, which can improve processing performance when drilling the workpiece material. Threaded chip flutes can remove splinters and debris faster. MATERIAL: Spiral drill bits are made of high speed steel with titanium coating, provide heat resistance and long service life.