High-speed steel, more durable. Coated to reduce friction and keep the temperature lower. Stepped drill bit. Widely used for drilling holes in various materials such as thin steel panels, wood, thin iron, aluminum alloys, insulation boards, PVC sheets, etc. No need for a pilot hole; automatic hole deburring during drilling. Special stepped structure allows drilling holes of different sizes. Water-cooled operation to effectively extend the life of the drill bit.