Features:* 7 different sizes, suitable for different needs. It can be installed in general electric hand drill, bench drill.* It is made of high quality YG6X alloy as raw material. Oxynitriding process cutting head strengthen the hardness of the drill bit.* Full grinding and anti-rust treatment, clean and sharp without burrs. The drill bit is more wear-resistant and more durable.* Fully automatic polishing: CNC polished is fully automated, each is unified.* Small notch resistance, stable drilling, speed, no limit breaking. Opening neat, smooth, no broken edges, no shaking phenomenon, easy chips.* Professional glass and tile drill bits provide smooth and accurate drilling in ceramic tile, marble, thin iron, mirrors and glass. Be sure to add water or coolant when drilling. Specifications:* Material: Cemented Carbide* Color: As the picture shown* Size: 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm* Quantity: 7pcsPackage Contents:7*Universal Drilling ToolNotes:1. The actual colors of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness.2. Please allow slight manual measurement deviation for the data.