ITEM NAME:1/4-inch Hex Shank 3-12 4-20 4-12mm Titanium Coated Step Drill Bit Set A5D1 1/4-inch Hex Shank 3-12 4-20 4-12mm Titanium Coated Step Drill Bit Set A5D1 Ideal for drilling shallow or deep holes in timbers and board materials. Straight grooves.10 steps size: 3, 4, 5, 6, 7, 8, 9, 10, 11, 12mm,9 steps size: 4, 6, 8, 10, 12, 14, 16, 18, 20mm,5 steps size: 4, 6, 8, 10, 12mm. A great helper for Carpenter. Product Name : Step Drill Bit Material : HSS,Titanium Coated Main Color : GoldTone, Silver Tone Hex Shank Size : 6.3mm/ 1/4inch Cutting Dia : 3-12mm, 4-20mm, 4-12mm Total Length : 78mm/ 3inch, 73mm/ 2.9inch, 67mm/ 2.6inch Weight : 97g Package Content : 3 x Step Drill Bits Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.