1. [] - Heat treated, durability, has high hardness, not easy to wear. PLEASE MAKE SURE YOU CHOOSE THE RIGHT DRILL BIT AND CONTROL THE RIGHT SPEED OF THE DRILL. THIS OPERATION GREATLY PROLONGS THE SERVICE LIFE OF THE HEX DRILL BITS. 2. [Professional Hex Bit Set Are Made of S2 Alloy Steel, Very Well Made And Tough As Nails] - Hardness can reach HRC60 degree. Hex key set fit for electric drills with speed regulating device, electric screwdrivers, hand screwdrivers. Please do not use drill bits on pneumatic tools, air dills, and the electric drill without speed regulation. A long lifetime of the drill bit is reached due to its durable construction and superior technology. 3. [Nickel Plating Surface Treatment, Super Anti-Rust] - , long lasting and durable. The Hex drill bit set is clearly marked that you can find what size you need quickly. Easy to take and use. 4. [Magnetic Tips And Arbitrary choice Length] - The hex screwdriver set is a little bit magnetic, which helps to keep nuts and bolts stuck to them. Can improve your work efficiency. Thumbs up!<br><br>Colour:As Shown Material:alloy steel<br><br>Package Contents: 1 * Cross screwdriver bit Kit<br><br>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.