General description 15PCS Diamond Drill Bit set includes drill bits with diameters of 6, 8, 10, 12, 14, 16, 18, 20, 22, 25, 26, 28, 30, 40, and 50 mm. These diamond drill bits are designed for use on glass, ceramic tiles, bottles, glass blocks, ceramics, marble stone slabs, perforated granite, and other hard surfaces, particularly effective on glass and ceramics. Technical specifications Material: High quality natural diamond sand Coating: Nickel-plated diamond dust Sizes: 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm, 22 mm, 25 mm, 26 mm, 28 mm, 30 mm, 40 mm, 50 mm Usage Water lubrication is recommended during drilling to enhance performance. It is important to reduce the speed of the diamond tip and apply low drilling pressure for optimal results. The drill bits can be used to cut holes diagonally, create circular connections, and drill holes accurately. Other information Note: These drill bits are not suitable for use with microcrystalline materials or certain surfaces and