[EXTREME HARD] These diamond drill bits are made of industrial-grade carbon steel with a nickel-plated coated body to resist corrosion. A thickened diamond coating on the tips offers superior cutting strength for maximum drilling performance. [EXTRAORDINARY SHARP] Each diamond hole saw has a smooth and precise finish that reduces incision resistance and drill pressure, increases sharpness, and enhances water lubrication efficiency. Ideal for making clean and precise holes in glass or ceramic, while significantly extending drill bit life. [LARGE CLEARANCE HOLE] The design of these glass hole saws allows for easy entry of cooling water and efficient removal of chips and debris during drilling, making the process smoother and more effective. [WIDE USAGE] This glass drill bit set includes 5 different sizes (4mm / 0.16 inch, 6mm / 0.24 inch, 8mm / 0.31 inch, 10mm / 0.39 inch, 12mm / 0.47 inch) to meet various drilling needs. Suitable for use on glass, tile, porcelain, ceramic, brick, and stone. Total length: approximately 2 inches Color: silver Material: carbon steel Dimensions: 10 x 6 x 3 cm Package Contents: 5 x Diamond Coated Drill Bits Note: Operate at speeds below 8001000 RPM. Low drill pressure and consistent water lubrication will help extend the life of the drill bits. Always apply water during use when drilling glass or ceramics. Package includes only the items listed above; other accessories are not included. Note: Lighting conditions and monitor settings may cause slight variations in color between the image and the actual product. Measurement tolerances may vary by 13 cm.