Sharp and durableSuitable for hard wood Drill Material: HSSChamfering device Material: SteelSize: 5# drill diameter 3.18mm 6# drill diameter 3.58 mm 7# drill diameter 3.97 mm 8# drill diameter 4.37mm 9# drill diameter 4.76mm 10# drill diameter 5.15mm 12# drill diameter 5.56mmPackage Included:7 x Drill