Quality Material - This drill is made of hard alloy, which is hard, strong, and durable. Self-tapping drill bits can be screwed in quickly and precisely without the need for tedious pre-drilling. No risk of cracks and crevices. Versatile - This drill bit is suitable for most drill models and can be tightened effectively with electric hand drills to prevent climbing and slipping, especially on metals due to its higher hardness. Widely Used - The drill kit is ideal for drilling into various materials including tile, concrete, ceramic tile, brick, wood, plastic, glass, and masonry. Note: When drilling hard materials such as glass, tile, marble, or granite, lubricate with water. Package Includes - Each package contains two styles: black triangle diamond and orange diamond, totaling 10 pieces. Sizes include 6mm, 6mm, 8mm, 10mm, and 12mm, meeting a variety of drilling needs.