General description High quality diamond drill bit set featuring 20 pieces in 4 different sizes: 1mm, 1.5mm, 2mm, and 2.5mm. These drill bits are suitable for use with drills, flexibles, and milling cutters, making them ideal for creating holes in various materials such as sea glass, shells, rocks, marbles, and gemstones. Perfect for crafting your own earrings, pendants, and bracelets. Technical specifications Sizes: 1mm, 1.5mm, 2mm, 2.5mm Material: Emery Color: Silver Package Contents: 40 x Diamond Drill Bits Measurement allowed error: +/- 1-3 cm