【Size】 4-12mm / 4-20mm / 4-32mm. Taper tip with a stair profile which is used to drill 19 hole sizes from 4-32mm to replace 19 individual drills. Auto-start , no breakthrough required. 【Material】 Made of high quality 4241 HSS (high speed steel) and titanium coated for longer life. 【Application】 Ideal for cutting holes in various materials including steel, sheet metal, wood, plastic, etc. This drill can meet your needs. 【Benefit】 Automatically deburr holes left by other bits as the large increase to the next step size allows the cutting edge to scrape burrs from the entry surface of the workpiece. Good chip evacuation and even cutting saves time and effort at the same time. 【Performance】 The length of the unit and the ability to vary the diameter of the finished hole is an advantage when working with a frame or front panels. The finished hole can often be made particularly smooth and burr-free, especially in plastic. Product feature: 1. No need for pilot drilling 2. Titanium coated to reduce friction and run smoother 3.The good bit has a 3-sided tree. 4.Automatically deburr holes as you drill, high speed steel, durable. 5. Widely used for cutting holes in a variety of materials such as steel, wood, thin iron, aluminum alloy, insulation board, PVC film, etc. Specification: Color: golden (shown as the picture) Material: high speed steel Surface: titanium coated Scop: thin iron plate, aluminum, insulation boards, 4mm thick PVC panels in wood. Size: From 4 to 12 mm 9 steps (4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm), 7 cm (L) 4 - 20 mm 9 steps (4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm), 7 cm (L) 4-32mm 15 steps (4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32 mm), 10 cm (L) Scope of delivery: 1 x twist drill 4-12 mm 1 x Spiral Grooved Drill Bit 4-20 mm 1 x 4-32 mm twist drill bit