Blue Diamond-Coated Hole Saw Drill Bits

Material and Coating: The cutting edges are coated with diamond grit for grinding through hard surfaces rather than chipping them.Included Sizes: The set appears to include multiple diameters, such as 18mm, 20mm, 25mm, 35mm, and 45mm.Application: These bits are typically used for drilling clean holes in fragile or hard materials like glass, ceramic tiles, porcelain, marble, and granite.