Excellent Material: The bit part is made of 4241 high speed steel, which has higher hardness and good cutting ability, can achieve fast drilling and provide long-term use. The black handle part is made of carbon steel, which can withstand high working pressure and is not easily braked. Precise punching: it can punch a hole quickly and accurately. And the outward thread design can help discharge waste chips when drilling, which can ensure successful drilling. Five Different Sizes: Included five countersink screw sizes: 5# 1.98mm , 6# 2.38mm, 8# 2.78mm, 10# 3.175mm, 12# 3.56mm Applications: It is suitable for drills with chucks or joints. It can be used to drill holes on hardwood and plastic boards 100% Satisfied Service: Sincerely hope that our products can give you a good experience and help. Within one month you purchase this product, you can enjoy a worry-free return. And any questions, please feel free to contact us, we will do our best to help you.