【Materials】The drill bit set is made of alloy as raw material. The oxynitride process of the cutter head strengthens the hardness of the drill bit. 【Surface Electrophoretic Painting Process】The drill bit set is fully ground and rust-proof, clean and sharp without burrs. The drill bit is more wear-resistant and durable. Fully automated polishing, polishing is fully automated, each one is unique. 【Unique Cross Angle Design】Small incision resistance, stable drilling functionality, fast speed, without breaking the border. Neat opening, smooth, no broken edges, no tremor phenomenon, easy chipping. 【5 Different Sizes】Suitable for your different needs. It can be installed in the general electric hand drill, bench drill. The clamping range of the machine drill is 10mm and above. 【Widely Used】Professional glass and tile drill bits provide smooth and precise drilling in ceramic tiles, marble, thin iron plates, mirrors and glass. Remember to add water or coolant when drilling. Specifications: Materials: Cemented Carbide Product Weight: 125G Product Size: 3*70/4*70/5*76/6*77/7*80MM Package Included: Universal Drilling Tool (5pcs) * 1 Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.Good quality product