Description:These high strength HSS constructed drill bits are perfect for drilling workpiece with the hardness below 25HRC, such as for carbon steel, sheet iron plate, insulating plate, PVC plate, wood board, etc. Features:4pcs HSS constructed drill bits for drilling holes with screw sizes #6,#8,#10 and #12.Special designed steel counter sleeve countersinks or counter bores hole.Adjustable counter sleeve depth with hex wrench.6.35mm standard hex shank is fast change compatible.Drill and countersink for wood screws without changing bits.Drilling length can be adjusted for various length screws simply by loosening and tightening the setscrew.Suitable for drilling workpiece with the hardness below 25HRC, such as for carbon steel, sheet iron.plate, insulating plate, PVC plate, wood board, etc. Use on a drill machine with chuck or connector.Specifications:Condition: 100% Brand NewMaterial: HSS 4241Color: As Picture ShownDrill Size: #6, #8, #10, #126#: 2.38mm8#: 2.78mm10#: 3.175mm12#: 3.56mmHex Shank Diameter: 6.35mm(1/4'')Other Size: As Picture ShownPackage Included:4 x Drill Bits1 x Hex Wrench.Note:Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.