High Quality: The drill bit is made of professional alloy steel. High hardness, strong and durable. It has good wear resistance and can be used longer than ordinary steel drill bits. Dimension: 10pcs drill bits. Size: 1/4. 6mm. Four-corner sharp chamfer design, easy and stable positioning, faster drilling speed, better stability, low fluctuation frequency and high efficiency. Hexagonal shank provides stable holding and quick release in the electric drill. 6.35mm hex shank for quick release. Application: Ideal for drilling ceramic tiles, glass, marble and mirrors. When drilling hard materials, please use water for lubrication, good cooling can extend the life of the drill bit. Please try to keep the drill vertical and use water or coolant for lubrication when drilling. Do not use these drill bits to drill hard tiles. Tungsten Carbide Tip: The bit features a tungsten carbide tip for increased efficiency and durability. Professional grade alloy steel, provides smooth and precise drilling