ITEM NAME:7 Pcs 1/4 Inch Hss Spiral Hex Shank Combination Drill Screw Tap Bit Set(M3- I2S1 7 Pcs 1/4 Inch Hss Spiral Hex Shank Combination Drill Screw Tap Bit Set(M3- I2S1 High hardness,rustproof,solid and durable.The advantage is opening,tapping,chamfering. Self-centering point,do not need assistant center drilling or center punching. Drilling and tapping in one,one-step processing,greatly save processing steps and time costs,improve working efficiency. Save processing steps and time costs,improve efficiency.Spiral groove,within the processing thread,cutting up to exclude,and was curled applied internally threaded through holes Color:silver+gold Material:HSS Package Contents: 6 *(M3 M4 M5 M6 M8 M10)1 each 1 * center punch.6 (M3 M4 M5 M6 M8 M10)1 each.