Feature:1. DRILLING DIAMETER: The drill bit is 9 steps design, with drilling diameter of 5mm, 7mm, 9mm, 11mm, 13mm, 15mm, 17mm, 19mm, 21mm, to meet different needs.2. 4 SPIRAL FLUTES: The step drill bit is 4 spiral flutes design, the incisive blades ensure faster and smoother cutting, greatly improving work efficiency.3. M35 COBALT METAL: This spiral flute drill bit is made of M35 cobalt high speed steel with a surface hardness of 89HRC, and can quickly cut hard materials.4. APPLICABLE MATERIAL: Very suitable for cutting wood, plastic, stainless steel, aluminum plate, copper, and other metal plates, convenient and practical.5. WITH 1/4 INCH SHANK: This step drill bit has a standard 1/4 inch shank, which can be easily installed on the appropriate power tools to use, stable and reliable.Specification:Item Type: Step Drill BitMaterial: M35 Cobalt High Speed SteelDrilling Diameter: 5mm, 7mm, 9mm, 11mm, 13mm, 15mm, 17mm, 19mm, 21mmShank Diameter: 1/4 Inch.Package List:1 x Step Drill Bit1 x Storage Box