90 PCS Excellent for fine detail work, cutting, engraving, carving, touching up and finishing, working on glass, metal, stone, ceramic, wood, plastic 30 different style router bit can achieve more carving, ideal for all types of detail work in glass, metal, stone, ceramic, wood, plastic Jewelry Beach Sea Glass Shells Gemstones Lapidary, Necklaces Earrings, Pendants, Bracelets, Beach, Tile, Marble, Rocks, Ceramic, Porcelain, Coated Burrs Drill Bits 1/8 inch diameter shank, compatible with most rotary tools, ideal for home improvement, hobbies, crafts and anytime you need to polish, grind, drill, cut, engrave and more with most rotary tools Material: Alloy; Diameter: 3mm / 0.12 inch CAUTION: DO NOT OPERATE DRY - Wet drilling only. These are delicate diamond drill bits, very small diameter. The diamond coating is very thin. Can't take abuse. - Start the hole at an angle. While holding the drill by hand, carefully move the drill just enough to scroll the sides of the hole. Let the tool do