1、Made of high speed steel, have high performance and durability, and with Ti coating, possess high hardness and stable performance, can penetrate metal, hardwood and plastic 2、120Pcs drill bit set contain 6 different length sizes of 30MM, 40MM, 45MM, 55MM, 65MM, 70MM, enough quantitative drill bits can meet your needs for regular replacement 3、Possess extremely high hardness, excellent processing performance in drilling processing, twisted design is easy to self center, and can prevent walking. All drills have a smooth surface and no burrs 4、Twist drill bits are suitable for cast iron, copper, aluminum, plastic and wood, very powerful 5、The product is a good choice for automobile spring steel, mold steel drilling, DIY, household and general construction, engineering