CROWNMAN HSS twist drill series is divided into three types. The professional type is made of M35 material, produced in accordance with DIN338 standard, grinding production process. The head opening angle is 135°, and the drilling is very sharp. It is suitable for drilling of various plates and non-ferrous metals. The classic model is M2 material. Its production standard, process, and opening angle are the same as those of the M35 drill, but the hardness is higher. When drilling holes in stainless steel, the relative number of holes will be 1/3 less than the M35 bit. Basic models are affordable and suitable for home use, mainly sold in sets. It is a low-grade high-speed steel material with a hardness of about 60°, which can be used for continuous drilling of iron plates and non-ferrous metals.