HIGH-QUALITY MATERIALS: It is made of high quality Cemented carbide material. The process of oxynitriding of the cutter head strengthen the drill hardness.SURFACE ELECTROPHORETIC PAINT PROCESS: Full-grinding and anti-rust treatment, clean and sharp without burrs.The drill bit is more wear-resistant and more durable.Fully automated polishing: Polished CNC is fully automated, each one is unified.UNIQUE ANGLE DESIGN: Small incision resistance,feature drilling stably, fast speed, not breaking the border. Opening neat, smooth, no broken edges, no tremor phenomenon, chip easily.WIDE USAGE: glass and tile drill bits provide smooth and accurate drilling in ceramic tiles, marble, thin iron plate, mirrors and glass. Remember to add Water or coolant when drilling.5 DIFFERENT SIZES: Suitable for your different needs.It Can be installed in the hand drill, bench drill. The actual color is slightly different, 3+4+5+6+8mm is 1 setMaterial:Cemented carbidecolour:Photo ColorPackage Contents:5 * Universal Drilling ToolOnly 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.