HIGH-: It is made of high YG6X alloy as raw material. The process of oxynitriding of the cutter head strengthen the drill hardness.ultimate drill . 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: is fully automated, each one is unified.Triple-Cornered Drill Bit. UNIQUE DESIGN : Small incision resistance,feature drilling stably, fast speed, not breaking the border. Opening , , no broken edges, no tremor phenomenon, chip easily. ,Glass Drill Bit. WIDE USAGE : Professional glass and tile drill and drilling in ceramic tiles, marble, thin iron plate, and glass. to Water or coolant when drilling. ,Concrete Drill Bit Set. DIFFERENT SIZES : Suitable for your different needs.It Can be installed in the universal electric hand drill, bench drill. The machine drill clamp range is 10mm and above. Tile Drill Bit,Masonry Drill Bit Set. colour: Material: Alloy Package Contents: 5 x Universal Drilling Tool(3/4/5/6/8mm) 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.