Features DRILL BIT SET: The kit includes a drill bit and 5 step drill bits, with specifications of 1/4 to 1 3/8 inch, 3/16 to 7/8 inch, 1/4 to 3/4 inch, 3/16 to 1/2 inch, 1/8 to 1/2 inch. 4 FLUTE: These step drill bits have four spiral flutes, the four cutting blade design ensures faster and smoother cutting. 1/4 INCH SHANK: These drill bits have standard 1/4 inch shank that can be seamlessly connected to the electric drill, easy to install. HIGH HARDNESS: The step bits are made of M35 and cobalt, with a surface hardness of 89HRC, and can cut harder materials. MULTI PURPOSE: These drill bits are very suitable for stainless steel, metal plates, wood, plastic, aluminum plates, copper and other metal plates. 1. DRILL BIT SET: The kit includes a drill bit and 5 step drill bits, with specifications of 1/4 to 1 3/8 inch, 3/16 to 7/8 inch, 1/4 to 3/4 inch, 3/16 to 1/2 inch, 1/8 to 1/2 inch. 2. 4 FLUTE: These step drill bits have four spiral flutes, the four cutting blade design ensures faster and smoother cutting. 3. 1/4 INCH SHANK: These drill bits have standard 1/4 inch shank that can be seamlessly connected to the electric drill, easy to install. 4. HIGH HARDNESS: The step bits are made of M35 and cobalt, with a surface hardness of 89HRC, and can cut harder materials. 5. MULTI PURPOSE: These drill bits are very suitable for stainless steel, metal plates, wood, plastic, aluminum plates, copper and other metal plates. Specification: Item Type: Step Drill Bit Set Material: M35, Cobalt Shank Diameter: 1/4 Inch Hole Diameter: 1. 1/4 to 1-3/8 inch 2. 3/16 to 1/4 to 5/16 to 3/8 to 7/16 to 1/2 to 9/16 to 5/8 to 11/16 to 3/4 to 13/16 to 7/8 Inch 3. 1/4 to 5/16 to 3/8 to 7/16 to 1/2 to 9/16 to 5/8 to 11/16 to 3/4 Inch 4. 3/16 to 1/4 to 5/16 to 3/8 to 7/16 to 1/2 Inch 5. 1/8 to 5/32 to 3/16 to 7/32 to 1/4 to 9/32 to 5/16 to 11/32 to 3/8 to 13/32 to 7/16 to 15/32 to 1/2 Inch packing list: 5 x Step Drill Bit 1 x Drill Bit Package List 5 x Step Drill Bit 1 x Drill Bit