These taps are made of high speed steel and surface coated by nitriding for high hardness and rust resistance. There are a total of 6 taps in different sizes from M3 to M10 that you can use with different taps The taps are designed with spiral flutes and the chip cleaning process would be better These are taps with drilling function that are used to drill a hole and cut new threads at the same time. With them, you get a smooth thread cut. These taps are used on a machine for thread cutting. This is generally more accurate as it eliminates human error