General description High-quality diamond-coated drill bits designed for precision drilling in various materials such as sea glass, shells, rocks, marbles, and gemstones. This set includes 20 pieces in four different sizes, making it ideal for jewelry designers looking to create custom pieces like earrings, pendants, and bracelets. Technical specifications Sizes: 1mm, 1.5mm, 2mm, 2.5mm (5 pieces of each size) Material: Emery Color: Silver Measurement allowed error: +/- 1-3cm Compatibility and accessories Suitable for drills, flexible shafts, and milling cutters Other information