Item Description:Suitable for workpieces with a hardness of 25HRC or less, such as iron plates, aluminum plates, PV plates, insulating plates, etc.A drill can drill a variety size of holes to meet yourneeds.It is possible to r, chamfer, and open-hole reaming that twisted drills cannot be completed.Compared with the ordinary twisted drill, the sway is small, and the aperture can be opened without using the center punch.The drills are made of high speed steel which is durable and has long service life.Specification:Material:High Speed SteelSize:6 Levels : 3/16",1/4",5/16",3/8",7/16",1/2"9 Levels :1/4",5/16",3/8",7/16",1/2",9/16",5/8",11/16",3/4"13 Levels :1/8",5/32",3/16",7/32",1/4",9/32",5/16",11/32",3/8",13/32",7/16",15/32",1/2"Package List:3* Step DrillAboutItem Specification:DIY Supplies: WoodworkingType: OtherUse: Wood Drillingis_customized: YesMaterial: High Speed Steel