Surface treatment: Nitride blackApplication: Suitable for drilling and hole reaming processing of wood, aluminum, plastic board, insulating board and other materials with a thickness of less than 5mm.Specification:4-20 (9th order):4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm3-12 (Tier 10):3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm4-12 (5th order):4mm, 6mm, 8mm, 10mm, 12mmColour:blackMaterial:high speed steelPackage Contents:1 * 4-20mm (9 step) drill bit1 * 3-12mm (10 step) drill bit1 * 4-12mm (5 step) drill bitOnly 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.