Made of high speed steel, which can sharp, fast execution and retain strength and efficiency. The surface is treated with a titanium alloy, which greatly improves the cutting performance of the drill. Each tap drill is with a label, which is convenient for you to the size suits you. The convenient hex has a tapered end to prevent excessive knocks. Back taper exceeds the tap to prevent over-drilling and damage to the thread. They are taps with drilling function, three-in-one operation, which can drill, tap, deburr and counter holes on copper, brass, aluminum, metal and plastic at the time. Metric:M3X0.5,M4X0.7,M5X0.8,M6X1,M8X1.25,M10X1.5 SAE:1/4-20NC,12-24NC,10-24NC,10-32NC,8-32NC,6-32NC Colour:blue + gold Material:HSS Package Contents: 12X Screw Tapping Bit Only the above package content, other products are not included. Note: Light reflection and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.