Glass Drill Bit These diamond drill bits are made of industrial-grade carbon steel with a nickel-plated coated body to resist corrosion. Fine workmanship and super wear-resistant for sharp, durable performance. High-Quality Drill Each hole features a smooth and accurate surface treatment, and the top of the hole is thickened to achieve excellent cutting strength. Tile Hole Saw – 15 Sizes 6, 8, 10, 12, 14, 16, 18, 20, 22, 25, 26, 28, 30, 40, 50 mm Designed to meet various drilling needs. Wide Usage Suitable for use on glass, wood, tile, bottles, blocks, jars, ceramic, slate, marble, granite, light stone, and other hard surfaces. Attention Always add water when using diamond drill bits on glass or ceramics. Low drill pressure combined with sufficient water lubrication helps extend the life of the drill bit.