Drill tip is made of hard metal, tungsten carbide, which is extremely durable and can withstand the friction of drilling into glass Compatible with almost all power drills cordless drivers Its spade-shaped bit point especially works with glass and other hard but fragile materials like tile, ceramic, bricks and brickwall Threaded shank also makes it be able to work with wood, stone, concrete and other general purpose Useful small hand drill for precise drilling, electronic assembling, tool making, model making, jewelry engraving, and hobbies Specification: Diameter: approx. 6mm/ 8mm/ 10mm/ 12mm Drilling Objects: Masonry, Cement, Ceramic Tile, Brick, Block, Rock, Stone, Concrete, Metal, Plastic, Wood, etc. Suitable Usage: Home Decor, Walls Perforation, Wire Switch Installation, Closet Installation, Installation of Lamps Color: as shown in display pictures Surface is sprayed of metal paint to prevent from rusting. Package Includes: 2 Pieces 6mm Glass Drill Bits 1 Piece 8mm Glass Drill Bit 1 Piece 10mm Glass Drill Bit 1 Piece 12mm Glass Drill Bit Note: Please work carefully and safely. You should wear gloves and protective eyewear so that you won't be cut by any glass shards that break off. You will need some kind of liquid to lubricate the drilling process and to keep the drill bit from overheating.