steel hardness can reach HRC60 degree Please make sure you choose the right drill bit and control the right speed of the drill This greatly prolongs the service life of the drill bit for industrial maintenance in manufacturing electronics and automotive industry as well as household repairs and projects Heat treated durability has high hardness not easy to wear The allen screwdriver is which helps to keep and bolts stuck to them Can improve your work efficiency Welcome to inquire, Manufacturer: FNFTOEZGY