Surface treatment: Nitride black Application: 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, 20mm 3-12 (Tier 10): 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm 4-12 (5th order): 4mm, 6mm, 8mm, 10mm, 12mm Colour:black Material:high speed steel Package Contents: 1 * 4-20mm (9 step) drill bit 1 * 3-12mm (10 step) drill bit 1 * 4-12mm (5 step) drill bit Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.