Automatically Deburrs Holes As You DrillTwo-Flute Design Gives You Faster And Smoother CuttingTitanium Nitride Coating For Cooler RunningQuick-Change 1/4 inch Hex High Speed Steel For Long LifeColor: golden yellow + silvermaterial: metalThese Step Drill Bits Are perfect For Variety Of Materials From Metal, Plastic, Fiberglass To WoodThey Also Help To Enlarge Existing HolesThe Two Flute Design Tips Can Make The Penetration Faster Without Chipping1/4 inch Hex Sizes: (approx.)3-12mm:3, 4, 5, 6, 7, 8, 9, 10, 11, 12 mm/ 012, 016, 020, 024, 028, 031, 035, 039, 043, 047 in4-12mm:4, 6, 8, 10, 12 mm/ 016, 024, 031, 039, 047 in4-20mm:4, 6, 8, 10, 12, 14, 16, 18, 20 mm/ 016, 024, 031, 039, 047, 055, 063, 071, 079 in4241 High-Speed Steel HSS (Suitable For Use In The Workpieces Whose Hardness Is 25 Degrees Such As Carbon Steel, Plate, Insulation Board, and Wood Board)Packing list:3 * Step Drill Bit With BagOnly the above package content, other products are not included.Note: Light 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.