"1. Wide Range of Sizes: Including 7 Pieces of Plain Center Drill Bits Set range in size 1.0mm 1.5mm 2.0mm 2.5mm 3.0mm 4.0mm 5.0mm to meet different needs 2. Accurate: A 60-Degree Angle center drill is very useful in drilling accurate center holes, 60-degree countersink holes or starter holes for bigger drill bits in metal-working. 3. High Quality: Our center drill bits made of high quality M2 High speed steel, solid and high temperature wear resistant. 4. Widely Applicable: work with lathe machines and most electronic drills to drill holes in Steel, Iron, Alum, Carbon Steel, Brass and other tough material ranging from 170HB up to 200HB. 5. This Center Drill Bits set comes with a portable storage case for convenient use and store."