Product Description AUTO DELLO drills are made from alloyed cobalt tool steel R6M5K5 Cobalt 5%. The cobalt included in the steel composition allows it to maintain hardness at high temperatures, which is especially important when drilling difficult-to-machine stainless steels. - They have high wear resistance. - The drill tips are sharpened crosswise at an angle of 135°, which allows drilling of high-hardness metals. - Hardness is 64-67 HRC. - Packed in an envelope with a hole for convenient storage. Using drills with increased wear resistance and hardness allows for significant time savings in drilling and simplifies the work of the automotive master several times.