Comprehensive & Compatible Tool Set - 5 Pcs Dry Diamond Core Drill Bits kit diameter of 1/4 inch(6mm)x2, 5/16inch (8mm), 3/8inch (10mm) and 1/2inch (12mm) for drilling holes. Advanced Dry Drilling Technology - each tile drill bits is equipped with an internal wax lubricant that melts during use to cool the cutting surface, preserving the integrity of the diamonds and extending the life of your bits. Precise Drilling - Achieve holes with the vacuum brazed diamond technology that ensures a clean and precise cut every time. Perfect for drilling holes in porcelain, , ceramic, glass, marble, stone, and more.(not for wood). Universal 1/4 inch Hex - Compatible with the most electric drills, angle grinders, and bench drills. Quick change is facilitated by the hex , improving efficiency and reducing downtime between drill bit changes. Enhanced Durability - Dry diamond drill bits set featuring a robust design that resists wear and tear. Perfect for both professional and DIY projects, this set ensures a long-lasting performance even when drilling through the toughest materials like porcelain tile and glass. Material: steel colour: As shown Package Contents: 5 x core drill Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.