High Quality Material: Carbide alloy head with stronger hardness. Carbide tipped drill bits are designed to last and stay sharp much longer than typical steel drill bits. U-shaped slot design: U-shaped slot with fast dust removal, triangular handle, more stable operation. Wide range of applications: sturdy tungsten carbide tip that can easily penetrate various materials (porcelain tile, glass, mirror, plastic masonry and wood). When you use the drill bits to drill concrete, brick walls and other hard materials (glass, tile, marble or granite), please use water for lubrication. 7 different sizes: 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm. 3 flat shank, these glass drill bits perfectly adapt to different drilling tasks, high drilling precision. Rotating thread cutting, smoother drilling and chip removal. First-class performance: This heavy-duty tungsten carbide tipped drill bit is sharp, easy to locate, stable when drilling, fast speed, no edge breakage, clean, smooth opening. The 3-flat