zvd 3pcs brand step drill bits, titanium coated high speed steel 3 12mm, 4 12mm and 4 20mm

3 standard sae step drills can drill 28 different sized holes in materials of different thicknesses. the 3 drills are available in the following sizes 4 to 12 mm 4 mm, 6 mm, 8 mm, 10 mm or 12 mm. 4 to 20 mm 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm. 3 to 12 mm 3 mm, 4 mm, 5 mm, 6 mm