[EXTRAORDINARY ]Each hole saw has a smooth and exact finish that lower the incision resistance and drill pressure, increases the sharpness, and effectiveness of water lubrication. Excellent for making clean and precise holes on glass or ceramic and considerably extending drill bit life. [EXTREME HARD ]These drill bits are made of industrial grade carbon steel with -plated coated body to resist . A thicken coating on the tops offers superior cutting strength for maximum drilling outcomes. [LARGE CLEARANCE HOLE]These glass hole saw set along the drill bit facilitate the entrance of cooling water and escape of chips and other particles from drilling. Makes the drilling process easier. [WIDE USAGE] 5 varied size drill bits (4mm/0.16inch , 6mm/0.24inch , 8mm/0.31inch , 10mm/0.39inch , 12mm/0.47inch ) included with this glass drill bit set to meet various demands. Perfect for drilling glass, tile, porcelain tile, ceramic tile, brick, and stone., Manufacturer: Littimoon