Material: high-speed steel. Ground straight tap set with step and 1/4" hex drive, HSS for M3, M4, M5, M6, M8, M10 for high requirements on process reliability and tool life. High hardness, quick exchange of the composite membrane, uses the edged drilling principle. Drilling and tapping in one processing, one-step processing. Solid processing steps and time saving improve work efficiency. The spiral taper design prevents thread damage due to over-drilling. Same centering point, no need for center drilling or punching. The design allows drilling, tapping, deburring and countersinking in wood, plastic, thin aluminum, copper and other soft metals (5-6 mm), not for hard materials (e.g. example, steel plate). Package Included: 6pcs tap (M3, M4, M5, M6, M8, M10). Note: When drilling a hole, you need to inject water at the same time to cool the drill. This will help you increase the value of the drill. If you cannot cool the drill bit while drilling holes, the drilling speed should not be too high and you should not drill too often. 6pcs 1/4'' HSS Screw M3-M10 Hexagon Countersunk Head Hand Drill Bit Set Machine Hand Drill Drilling and tapping in one processing, saving many steps and working time, improving work efficiency. Self-centering tip, does not require assisted center drilling or punching central. Combining drilling and tapping in one operation and with conventional drills is fantastic. The design allows drilling, tapping, deburring and countersinking in wood, plastic and thin copper-plated aluminum (5-6 mm), not for carbide. Suitable for drilling, tapping, cutting on soft metal, aluminum sheet, iron, etc. Parameters: Material: High Speed Steel Color: As shown in the picture. Size: As shown Package includes: 6pcs countersunk head (box in plastic) Description: The screw drill bit set is made of high speed steel, with high hardness and good abrasion resistance. It includes 6 drill bits from M3 to M10. Compact and portable, this tool set is perfect for drilling and tapping, suitable for soft metal. Specifications: Condition: 100% Brand New Material: HSS4341, HSS6542 Titanium Plated (Optional) Size: M3*0.5mm, M4*0.7mm, M5*0.8mm, M6*1mm, M8*1.25mm, M10*1.5mm Weight: Approx. 61~85g Package Included: 6 x Tap Drill Bits