Perfect for Sea Glass, Stones & Jewelry Making: Drill clean holes through sea glass, shells, , quartz, , and gemstones. Ideal for creating pendants, necklaces, and wire-wrapped jewelry pieces. Water Cooling Extends Bit Life: For thick materials like glass and stone, submerge in water or use continuous water to prevent overheating and cracking. Thin shells may not require water cooling. Premium 120 Grit Coating: High-quality grit coating provides smooth, precise holes. Twist drill design with matching collets ensures stable drilling without slipping or wandering. Complete 20Pc Drill Bit Set with 4 Collets: Includes 5 each of 1mm, 1.5mm, 2mm, 2.5mm coated twist drill bits. Each size comes with matching brass collet for secure fit in and similar rotary tools. Four Versatile Sizes for All Projects: 1mm to 2.5mm range covers pilot holes to larger pendant holes. pack for hobbyists, jewelry makers and ., Manufacturer: Akfldms