90 PCS Excellent for fine detail work, cutting, engraving, carving, retouching and finishing, work on glass, metal, stone, ceramic, wood, plastic 30 Little Different Style Router Can Achieve More Carving, Ideal For All Kinds Of Glass, Metal, Stone, Ceramic, Wood, Plastic, Detail Work Beach Jewelry Sea Glass Seashells Lapidary Gemstones, Necklaces Earrings, Pendants, Bracelets, Beach, Tiles, Marble, Rocks, Ceramics, Porcelain, Coated Burrs Drills 1/8 '' diameter shank, compatible with most rotary tools, ideal for home improvement, hobbies, crafts and any time you need to polish, grind, drill, cut, engrave and more with most rotary tools Material: Alloy; Diameter: 3mm / 0.12 inches CAUTION: DO NOT RUN DRY - Wet drilling only. These are delicate diamond drills, very small in diameter. The diamond coating is very thin. I can't take abuse. -Start the hole at an angle. While holding the drill in your hand, carefully move the drill just enough to scroll through the sides of the hole. Let the