1、Steel Alloy: The electric screwdriver bit is made of S2 steel alloy material, which is induction hardened, impact resistant, tough and durable. 2、Magnetic Screw Bit: With strong magnetism, you can easily and quickly grasp the screw and fix it to prevent the bit from slipping off and improve work efficiency. 3、Application: Screwdriver bit set is suitable for 1/4 inch screwdriver, manual screwdriver, electric drill screwdriver, and general chuck of most hand electric drills. 4、Wide Range of Uses: Screwdriver bit set uaually use for home, telecommunications, automobile or mechanical maintenance work etc.. 5、7Pcs Screwdriver Bits Packages: The Lengths for ph2 screw bits are respectively 25mm, 50mm, 65mm, 70mm, 90mm, 127mm, 150mm.