Product Description AutoDrill bits are made of alloyed cobalt tool steel R6M5K5 Cobalt 5%. Cobalt included in the steel composition allows to maintain hardness at high temperatures, which is especially important when drilling hard-to-machine stainless steels. - They have high wear resistance. - The tip of the drills is sharpened crosswise at an angle of 135°, which allows drilling high hardness metals. - Hardness 64-67 HRC. - Packed in an envelope with a hole for convenient storage. Using drills with increased wear resistance and hardness significantly saves the time spent on drilling and greatly simplifies the work of the automotive master.