Features: Premium Quality -- Made from HSS steel; Heat treated and highly polished ensures outstanding durability and sharpness, cut more smoothly, can reduces the friction, runs cooler hence lengthening the service life. High Performance -- Ideal for Deburring, Chamfering, Cutting or expanding perfectly round holes in a variety of materials including steel, wood, , etc. Wide Compatible -- The hex 1/4inch shank is better clamped on the Pistol drill, Hand drill, Charging drill, Bench drill to slippage and shedding during the rotation. Meet Your Demands -- with the versatile step drill bit, you can process different kinds of diameter holes, which greatly saves you a lot of trouble. Great for steel sheets/ aluminum sheets/ copper/ / wood board and many other types of sheet metal with ease countersunk. Wide Application -- Suitable for Home DIY, and General Building/ Engineering Use. Specification: Material: High Speed Steel + Titanium Coating Color: Gold + Optional Step Size: 4-12mm 5 (4, 6, 8, 10, 12mm) 4-20mm 9 (4, 6, 8, 10, 12, 14，16, 18, 20mm) 4-32mm 15 (4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32mm) Hex Shank Diameter: 1/4in(6.35mm) Step Drill Length: 4-12mm Length: Approx. 4.5cm/ 1.8in 4-20mm Length: Approx. 7.5cm/ 3.0in 4-32mm Length: Approx. 10.3cm/ 4.1in Packing List: 1 * 4-32mm Step Drill Bits 1 * 4-20mm Step Drill Bits 1 * 4-12mm Step Drill Bits Premium Quality -- Made from HSS steel; Heat treated and highly polished ensures outstanding durability and sharpness, cut more smoothly, can reduces the friction, runs cooler hence lengthening the service life. High Performance -- Ideal for Deburring, Chamfering, Cutting or expanding perfectly round holes in a variety of materials including steel, wood, , etc. Wide Compatible -- The hex 1/4inch shank is better clamped on the Pistol drill, Hand drill, Charging drill, Bench dr