Features 4 SPIRAL GROOVES: Four cutting flutes design ensure faster and smoother cutting. Feels like a hot cutting butter! M35 COBALT HIGH SPEED STEEL DRILL BIT: Very suitable for cutting stainless steel, wood, plastic, aluminum plates, copper, and other metal plates. 89HRC: With a surface hardness of 89HRC, this step drill bit can cut harder materials and achieve higher cutting speeds. HOLE DIAMETER: With this step drill bit, you can complete holes with a diameter of 1/4, 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4 inches. 1/4IN SHANK: This drill bit with a standard 1/4in shank, ensuring a tight fit with corresponding power tools, choose with confidence! Specification: Item Type: Spiral Groove Step Drill Bit Material: M35, Cobalt Hole Diameter: 1/4, 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4 inches Shank Diameter: 1/4 inch Package List: 1 x Step Drill Bit 1 x Storage Box Package List 1 x Step Drill Bit 1 x Storage Box