DescriptionThese diamond drill bits are made of industrial grade high-speed steel to resist corrosion. Fine workmanship and super wear-resistant. Treated with smooth and accurate surface treatment to achieve excellent cutting strength.Features- Material: High-speed steel.- This diamond drill bit kit removes a complete circle from glass, marble, tiles, granite, ceramic or others.- They are perfect for drill glass, tile bottles, blocks jars, fiberglass porcelain tile ceramic, slate marble, granite light stone.- These diamond drill bits are made of quality steel that is durable and has a long service life.- Which are and good performance that excellent for making clean and accurate holes.- No need to worry about scratching your tile when drilling the hole.