7 sizesThe drill bit set has 7 different sizes: 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm. These glass drill bits are very suitable for various drilling tasks, with high drilling precision, and can be installed on electric drills. High-quality materialsMade of high-grade steel head materials. cemented carbide, low strength, high hardness, improve work efficiency, and can maintain longer cutting edge time than ordinary steel drill bits. U-shaped groove and triangular handle The spiral U-shaped is smooth and flat, and the drilling is smoother. Triangular shank design makes clamping tighter without slipping. Spear Tip DesignThis heavy duty tungsten carbide tipped drill bit is sharp, easy to locate, stable drilling, fast, never not break the boundary, and the opening is neat and smooth. Widely UsedThe drill bit set is suitable for drilling ceramic tile, concrete, ceramic tile, brick, wood , plastics, glass, masonry and other materials. It is widely used in home decoration, manual DIY and other scenes.