1,Excellent Alloy Material: This twist drill bit is made of excellent alloy material, which has high hardness and durability.  2,Hex Design: This twist drill bit features a hex design that allows for a larger contact area between the bit and the drill interface, providing better stability and reducing the risk of slippage and drill breakage.  3,4 Flute Drilling: This twist drill adopts four flute drilling, which is fast and accurate, and improves the working efficiency.  4,Multiple Sizes: This twist drill bit set has multiple sizes, from 3mm to 12mm, which can meet your different usage needs.  5,Convenient To Carry: This twist drill bit set comes with a storage case to keep the drill bits organized for easy storage and carrying. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Minnanxin