【Material】HSS 4241, classic high speed steel with titanium coating for strength and durability. 【Easy Drilling】The spiral flute design prevents metal fillings from flying out and eliminates chips faster, making drilling easier without heating. The slotted tip has a 118 degree angle to reduce slipping and increase wear resistance. 【Hex Shank for Quick Change】The hex shank fits easier and fits securely on all power tools, especially when it locks into the quick coupling. Change chuck. It is best to tighten the pistol drill to prevent it from slipping and peeling off when rotating. 【Wide Range of Applications】Perfect step drill, suitable for drilling holes in various materials: less than 3mm (iron). plate, copper plate, aluminum plate); within 5mm (wood, PVC board, insulation boards). Not suitable for hard and brittle materials such as stainless steel, glass, tiled floors, walls, etc. 【What You Get】3 HSS Step Drills (4-12 / 4-20 / 4-32. mm) + 1 Automatic Centering Punch + 1 Storage Bag